Depressed feeling from nipple stimulation

Okay so when my nipples gets stimulated, I get this weird "homesick" or sad feeling in the pit of my stomach. It's so bizarre. It happens when I'm in the shower and the water hits them or if I'm rub them myself. It's like a wave of sadness that makes me want to cry, that goes away when the stimulation stop. I never noticed it until my pregnancy now. Has anyone ever experienced this? It's uncontrable and over-whelming