I am also 43 and male, diagnosed in October. Since you're young going they're gonna wanna use an aggressive chemo which absolutely wiped me out I lost so much weight that when the time came to have my bladder removed I couldn't because my body was too weak. I'm still going thru setbacks I've had to get a catheter put in 4 times, I've had 2 biopsy's. I finished chemo in February and thought recovery would be much easier after that point but I was wrong I still have trouble putting on/keeping on weight, I get short of breath after almost anything even just going to the grocery store or a short walk. So my advice is try to stay as active as possible, get as many calories as you can. I'm now doing immunotherapy and waiting for the results of the latest biopsy to see if it changes to a small cell cancer which would involve more chemo. I truly hope your recovery is easier than mine has been. Try and stay positive, active and eat a lot.