Very painful lower back pain not much appitite feeling nauseeous

I had bladder cancer four years ago was cut out T1 Grade 3 . Followed up with 6 weeks BCG.
I have been feeling nausaus occasional vomiting, sever pain in the right side of lower back. A bit of a discharge looks like pus.Not feeling very well

With a history this serious it is imperative you seek medical attention in person rather than over the internet.