What do you think caused my IBS-C and Redundant colon?

Hi, I'm a 21 year old male. I was diagnosed with IBS-C and Slow Colonic Transit. The Gastroenterologist told me my colon is abnormally long and floppy for my age. He initially thought I had Sigmoid Vulvulus because during the Colonoscopy, my colon had flopped to one side which made it look like it was twisted. He said my colon is similar that of an elders.

So I asked him what causes it and he told me that it's something that typically happens after complication during birth.

But I find it odd that I suddenly get this now. Because I wasn't born with complication and I never had any problem with constipation until April this year.

So I looked back at what I went through this year. Here is a timeline of what happened:

End of February:
Food poisoning(vomiting) after eating takeaway sushi which contained salmon roe and other sushi.

Mid March:
Had Accident at work. I was in extreme stress and anxiety for 30 minutes.

21st of April:
Started getting bad sleep/wake cycle due to random work shift.

30th of April:
Travelled to Sydney. My stomach was fine and I could eat normally.

1st of May:
After I got back from Sydney, I went back to bad sleep/wake cycle and eating past midnight due to random work shift.

Before 10th of May:
I drank between 30 ml - 70 ml of 8 month old bottle of unrefrigerated Red wine which has been previously opened. 5 minutes later, I started getting acute stomach pain which lasted for 10 minutes. Maybe this was a sign that I had gastritis that I was unaware of because old Red wine is basically just a vinegar and it's harmless in small amounts, right?

10th of May:
I went to the doctor saying that I think I have IBS after telling him the feeling of incomplete evacuation and abdominal pain after eating. He told me "it's nothing" and prescribed me Buscopan Forte for 3 weeks.

I asked him if I should change my diet or stop drinking coffee and he said "no". I did not believe him but I dismissed me.

The medication only temporary treated my abdominal pain but the pain would come back after the medication weaned off. One day while on the medication, I was straining in the toilet in a squatting position as usual. But this time I heard my stomach gurgle and felt my lower abdomen physically drop. At the same time, the top of my rectum popped out(about 3 cm). It wouldn't go back in so I had to push it back in with my finger.

I think what contributed to this incident was me continuing to drink coffee which stimulated my pelvic muscle to push harder, straining in a squatting position and Bucopan Forte relaxing the colonic muscles.

13th of May:
I started getting severe constipation, feeling of incomplete evacuation and abdominal pain whenever I ate food. I also probably started getting mucous discharge around this time. I went back to the doctor but they made me get blood tests, stool samples and X-ray before prescribing me anything.

9th of June:
I drank a sip of carbonated drink which caused my abdomen to become suddenly bloated like a balloon for 5 minutes. It was so painful that I thought my colon was going to explode. But after 5 minutes, thankfully all of the gas escaped somewhere else.

24th of June:
Diagnosed with Fecal impaction and I was finally prescribed laxatives 6 weeks after I had visited the doctor.

Until 22nd of August:
I continued to have constipation and abdominal pain after eating. But for the next 2 months, the doctor would only prescribe me stimulant laxatives whenever I went to see him.

This is how much stimulant laxatives I've taken in total:
Bisalax(5MG)
Took 52 tablets:
- 42 tablets in 3 weeks(2 tablets every night) when I was first prescribed
- 10 tablets(1 - 2 tablets at night) occasionally when I became incompetent.

Coloxyl and Sena(8mg Senoside)
Took 40 tablets:
- 30 tablets in 2 1/2 weeks(2 tablets every morning and night)
- 10 tablets(2 - 4 tablets a day) used occasionally after been prescribed a second bottle.

22nd of August:
Changed the doctor and he cured my abdominal pain with Nexium. He said I probably had Gastritis.

24th of October:
Had a Colonoscopy because I was still getting chronic constipation, feeling of incomplete evacuation and mucous discharge.

Present:
Diagnosed with IBS-C and Slow Colonic Transit.

This is pretty much what I went through this year. Does any one have any idea what could have caused my IBS-C and elongated colon? My guess is that food poisoning or extreme stress caused my IBS and Gastritis. And not having my constipation treated for 6 weeks to the point I developed Impacted Colon probably caused my Redundant colon.

So if my Redundant colon is caused by long-term constipation, will it return to normal length over time or is my colon going to stay elongated permanently?

The only symptom I get now is the need to pass mucus all the time and feeling of incomplete evacuation and slow bowel movement.

I'm able to relieve my IBS-C symptoms with the help of FODMAP diet, Probiotics, Digestive Enzymes, Aloe Vera, Peppermint, Slippery Elm and Psyllium Husk. But is there any way to treat slow bowel movement caused by a Redundant colon?

I too, have an abnormally long colon. I've suffered from chronic constipation since a child.  In October 2012

I underwent, yet, another colonoscopy and was again told my colon, was abnormally long. I Googled,  causes for constipation and redundant colon and found, both, can be symptoms of celiac disease. It is estimated 20% of people with diagnosed celiac experience chronic constipation. As well, there have been studies associating "mega colon" with celiac sprue. Presently, I have been gluten free for awhile and

I am experiencing regularity in terms of bowel movements. This, for me, is nothing short of a miracle...I've been reliant on laxatives for years. A host of other maladies have subsided as well...anxiety, runny nose, dry skin, etc., all, have diminished a great deal; In the past and more than a few times, I brought up the possibility of having Celiac or gluten intolerance to my gastroenterologist only to be told: "If you had Celiac, you'd be miserable. You don't have Celiac."   I was miserable! I was constipated all the time. The Doc didn't think I was miserable enough!

I strongly encourage you to research your heart out about celiac and gluten intolerance. Even, if you don't

test positive for Celiac, you may want to consider going gluten free for at least a year. Celiac is out there, in

untold numbers and is at the root of many miserable, medical mysteries.