I have just come out of hospital, is it safe for me to go to a concert?

I have just had part of my stomach removed and I'm having chemotherapy treatments. I'm in no condition right now and I have been warned and told to rest for pretty much the rest of this year but you see the thing is Muse are on tour. I have never missed a tour of theirs and often fly out to places just to see them play. In September they're playing in the UK and I really want to get a plane out and go to see them (plus the girl I really like is going watching them then and I thought I could surprise her by turning up). Will it be safe for me to go or should I just miss it this one time? I don't see why this should stop me from living my life so I really want to go but if it is going to make me worse then will it be worth it?