It's hard to tell how well Remicade is working for you because I don't know what your symptoms were before you started Remicade. I'm assuming they were worse than they are now. If so, Remicade is clearly doing something, even if it hasn't put you into 100% remission (yet). Rectal inflammation is usually the hardest to treat and the last to go, so maybe there's a bit of lingering rectal inflammation.
Personally I would have killed for those results on Remicade. But if it does bother you (and I'm not intending to guilt-trip you; hope it doesn't sound that way), maybe you need to do a quincy and bung in some rectal meds for a few weeks. Or just wait, as 5 infusions isn't that many and there's still time for Remicade to make further improvements.
Dx Crohn's in summer of 2000. (Yay )
Tried and failed: 5-ASAs, azathioprine, 6MP, Remicade, methotrexate, Humira, various diets.
Had surgery Feb '13 - subtotal colectomy with end ileostomy. First thing to put me into remission in 13 years.
Had second surgery 10th July '15 to reverse the stoma and connect the ileum to the rectum. Officially flaring again. The fun never begins.