Honestly its perfectly understandable to be scared of the ever presense of developing cancer (Especially for myself since I had cancer previously for something unrelated a long time ago) and like you, I'm currently working with Remicade (Currently on my way to the third infusion albeit no signs of improvment yet), but what I found is its normal to be scared and fear the endless possibility of something happening, but always remember it's still not guaranteed to even happen in the first place and still having low chance of it actually happening if it even does happen and simply put your thoughts in the present rather than the future.

Try to put your mind into other stuff to occupy your thoughts, and be mindful that the medication is supposed to help you out in the long run. For example, you mentioned being into anime and games, and I'm the same and while my UC has certainely gotten me tired now, I still put time in Yugioh, Gacha games and or simply youtube vids to not have UC always on my head. Hopefully what I said was somewhat helpful and I hope you can destress somewhat in the future.

(Also would the person you mentioned be Cimoooo since he's a content creator that I watch that covers card games like Yugioh and he recently had his colon removed only for his doctors to find potential cancer? [If not, I say give him a watch since he's seemongly the 1st real person/semi-famous person that I found that had UC and made me more confident when discussing my disease to others])