Girls, can you tell me I feel like my belly dropped already today, all…

Girls, can you tell me I feel like my belly dropped already today, all day I've felt like I want to go number 8 but nothing comes out, and I feel nauseous all day, maybe something is pressing on the baby? Or could this be some kind of premonition of labor? My stomach doesn't hurt, my lower abdomen isn't pulling, only when I lie down on my back it feels a little pinch...