Is it stupid that I'm not taking mecaptopurine with my infliximab?

I had 2 infusions so far along with steroid tapper btw and it's just the blood cancer risks thats baffling my mind to make a decision to take the immunosuppresant drug. So I've not been and don't feel like it. Idk maybe I should have faith in god and take it or have faith in god to not develop immunity to inflixi alone. I mean it is a cytotoxic idk. (I was good on Azathioprine thens suddenly it made me throw up 5-10 times every time I tried takin it even at low dose, I can't keep it down had to stop that).