What could it be?

My boyfriend and i dont use protection just the "pull put method" my period is due in 12 days so i know its early and it could be nothing but ive been exhausted, im always eating as if i never really get full, gassy, ive had headaches, my stomachs been bloated and sometimes i feel light cramps and tightness at the top of my stomach, and the smell of alcohol and cigarettes makes me nausous, and my boobs are soreee. 🤷🏽‍♀️