1St remicade infusion on Wednesday. Feeling rough as

So, decided to give remicade a go instead of entyvio. I have been doing well for a month, 2 bm's a day, no blood, energy back, all good. Consultant wanted to get me on biologics while I was well, as I'd made a miraculous recovery, but he said I'd slip back sooner or later. Anyway. Remicade Wednesday, blood almost immediately returned, and now up to 10bm's so far today. Along with it I feel like I've been run over by a bus. I Haven't felt as bad in years, along with nausea and dry heaving. Is this a bad reaction or is this normal. I'm feeling as rough as can be. Also annoying that is flared me up to this extent again. Should I continue with the loading doses or leave it? Don't think I could handle feeling like this again

Thanks for replying. Guess the most annoying thing is that the colitis is back in full effect. Although maybe it was never really away. I think I need to lower my expectations and come to the realisation there isn't a magic bullet.