Cannot have back support

Sandal

So I am FTM 34 weeks to be exact today. I am unable to have any sort of back support.. whether pillows or wedge or soft pillows.. my breathing gets interrupted its like the same feeling when i lay down straight. Now i know i cannot lay down straight but i cannot even give my back any sort of support for more than 2-3 min, i go out of breath. My back ache is killing me now :-/ anyone else experiencing the same?