So I am a 12B bra size. Last week I got a t-shit bra in my size which fits perfectly however I got a push up bra in the same size and the cups are seeming way to big for me. I did try it on in the changing room and it looked good then untill o started wearing it and adjusting the straps properly.

Is there a rule about push up bras I don’t know about? Any tips for next time