what do you do for pelvic and back pain ? help

Sheilasp
32wks +4 pain in back , pelvis 
Hello I'm in my 32wks n 3 days , feeling so tired sometimes I feel that I can't make it my back hurts so bad also my hips are milling me , the other thing is that I have a pain in my pelvis I try to ir my belt but after couple of minutes I feel like its tighten my belly so I tie it off, does anyone feels the same ? What do you do to release this pain I bought a Pilates ball to stretch a bit and also try to do the pelvic exercises but it seems Not time work . 
The other day I was in such pain that I cried I feel like I'm not going to make it and I have 7 weeks to go :(