Double Checking My GI's Plan

So my GI isn't that old, but he tends to respond to situations in old school ways, so I just wanted to ask you guys and see what you think about his behavior.

I'm soon to be 11 weeks postpartum, currently on remicade and a prenatal. I recovered incredibly well from my csection, never even had constipation, but after I got home, I had a lot of urgency after I ate. It was within minutes after dinner and Iwas running to the toilet with diarrhea. Sometimes I barely had time to finish dinner! I told this to my GI and he said it was because the hospital gave me antibiotics. Do you think that's true? I tested negative for streb b, so there was no reason to give me antibiotics and I don't remember taking any. Do they automatically give antibiotics with a csection? If so, then the sideeffects of these mystery antibiotics were pretty mild compared to what I've had with others, such as ciproflagyl, aka the one two punch that destroys my will to live by day 5.
Also, I told him how I suddennly had serious constipation a few weeks and bled enough to fill the bowl multiple times during my 7th week postpartum. He said I had a fissure, which is legit, but I wouldn't completely rule out other things since my disease activity is all focused on the rectum; it's where my fistula starts and any blood from the rectum also came out of the fistula.
Lastly, he said that I was due for colonoscopy, but decided to postpone it to the summer because I'm breastfeeding and he doesn't want me to have to pump and dump. Considering how I was on 6mp for the first trimester and I'm on remicade every six weeks, I was surprised to hear this about the colonoscopy drugs. Are they really so much worse or transfer to the breastmilk more than these other drugs? It seems hard to believe.
In the meantime, he told me to get some blood work done, but he also said that all my levels will be off since I'm 11 weeks postpartum, which suggests to me that even if they're severe, he won't give them an major concern.
I don't know, guys, what do you think? He's not a bad doctor, but I've learned in the past that I need to question his conclusions for my own security and health.

Not to mention trying to breastfeed through prep. I am sure your supply would just croak after evacuating all of those liquids to prepare for a scope.

I hope you want to breastfeed longer than a few months. If so, what is the rush to scope? The issues you're describing sound minor, plus if you are mostly concerned about the rectum you can do a flex sig in the office and no meds are necessary.

I had my first colonoscopy when my 2nd daughter was 30 months old. That was 3.5 years after I was diagnosed via flex sig - my symptoms started after the birth of my 1st daughter.

I was still nursing her at that point but so infrequently that the scope didn't make a difference.

My GI didn't examine me, which surprised me.
I haven't been on pain meds since day 2 postop, so I really don't understand why things just stopped moving all of a sudden!
I think my symptoms are minor too, but postpartum is a crazy time when anything can happen. I've been pretty lucky, so as a result, I'm always waiting for the axe to drop.
Also, family members on my mom's side have been having severe intestinal issues. My grandma had a rectovaginal fistula because of stage 4 colon cancer, which she survived, and my aunt, her sister, was diagnosed with diverticulitis today. My mom is going in for her 1st colonoscopy next week and I'm hoping that she's going to be diagnosed with IBS and nothing worse. She's had chronic constipation my whole life.
But thanks for the responses, guys!
I just wanted to double check.

I can only answer your question on breastfeeding. There is no such thing as pump and dump anymore (except in exceptional cases), because very little is transferred to the breastmilk. I had a colonoscopy a month ago and I breastfed my baby right after. Dehydration won't affect your supply (I'm referring to the prep here). Just before the prep, I had a gastro bug for a week... so I basically flushed for a week before my scope! No problem with my supply. In fact, your milk will get all that it needs... think about those women in third world countries, who are malnourished, and yet are still producing good milk. Also, I had my gallbladder removed a few months ago and breastfed by daughter right after, even though I got quite a bit of sedating meds. The idea is that if you are well enough to hold your baby, the amount of drugs in your system is low enough to be safe. They even gave me dilaudid after my delivery at the hospital! You can look up Dr Sears or Kellymom as well as Infantrisk to get more info on breastfeeding and drugs.