low confidence in bed

hi! i’ve recently gained about 20lbs. and although i’m not overweight by any means i am still very self conscious in the bed room now… i needed to gain this weight because my body was not healthy. but now i am self conscious in almost all positions my bf try’s to put me in. it’s really taking a toll on our sex life. the only position i feel comfortable is is missionary with a tshirt on😭 does anyone have an advice or any positions or anything that can make me feel more comfortable? my “problem” areas are my thighs and stomach.