I don't know if this helps, but here is how it all began with me.
After the birth of my first child at age 26, I began having blood in my stool. Bright red.
Told OB/GYN who said it was due to hemmorhoids.
Kept having blood and it increased. Started being able to eat anything but never gained weight. Started losing weight.
Got pregnant with my second child three years later and began having bloody diarrhea. Told new OB/GYN. He told me to be happy that I wasn't constipated. Told me I had hemmorhoids. Neither doc ever checked me, by the way, for hemmies.
Had bloody diarrhea and increasing pain in rectum during pregancy.
After my son's birth, I began having severe pain in my rectum and lower abdomen. I had bright red blood with every bowel movement. The BM's mostly were watery type mixed with blood, pus and or mucus. The entire toilet bowl was red and you could not really see the stool. I lost all my pregnancy weight (24 pounds) in about a week.
about seven months after the birth of my son, I lost another 20 pounds in about three more weeks. I was already very thin to begin with and really didn't have any to lose. I could not really eat much. Any food or drink would cause me to go straight to the bathroom. OB/GYN still told me I had hemmorhoids (and yet still no exam for them) and gave me a referral to a surgeon. I was having about 20 - 30 BM's a day. All were bloody with pus and/or mucus. I had low grade fever, joint pain, eye pain and severe lower abdominal pain. I had extreme rectal pain. The pain in my abdomen was low and on the right side. Sometimes it radiated down my right leg.
Went to that surgeon who told me that I didn't have hemmies. He said I had the longest and widest anal fissure he had ever seen. Wanted to operate. I hesitated (thank God as that would only have made things worse) and decided to wait. Meanwhile, the weight loss and blood loss were making me very weak. Finally, I fainted and my husband took me to the ER. It was there that the doctor suspected either E.Coli or Crohn's. This was the first real exam I had gotten related to my issues. I had pain when he pressed pretty much anywhere on my abdomen. They took a stool sample and it was just blood and pus. I had a fever (101 or so) and was anemic. I was sent to a GI who finally diagnosed Crohn's after doing the colonoscopy.
It took nearly four years for the diagnosis after initially seeing the blood in my stool. I realize now though that I probably had it much earlier (when I was a child) when I used to get very bad appendicitis-like pain at times, accompanied with diarrhea. For those times, our general doctor would always kind of roll his eyes and tell my mother that I just had a little stomach bug. We didn't have much money and I felt bad using it to go to the doctor, so I just pretty much tolerated it through the years and didn't go to the doctor because it was "just that stomach bug" again.
I hope this information helps. Sorry it was so long.