Heavy boobs on belly

Okay I cannot be the only person experiencing this, when I'm sitting unless my back is perfectly straight (and let's be honest who sits like that comfortably?) My boobs rest on my belly and it is the most uncomfortable thing ever. It almost makes it like I can't breathe. I need someone to stand behind me at all times just to hold my boobs up! I've tried different bras spent way too much money on different maternity and nursing bras that feel like they're suffocating me when I'm wearing them..the only bras I still wear are my sports bras but now they're getting a bit too tight around the band. Anyone else with this problem??