Upper and lower back problems...

I found out in January of this year that I have degenerative disk disease in T6-7 T8-9 and also T11-12. I also have a bulging disk in the T6 area, and went to therapy for compression fracture in my T12. I am at loss for what to do to build muscle, build up my booty, widdle my middle, and beef up my upper body. I was told by my doctor that I can't lift anything heavier than 15 friggin lbs!!! I went from 156 to 141 and don't really want to lose any more weight because I'm 5'8. So what can I do??? PLEASE help!!! Thanks in advance.