What should I do ?

In pain. Feeling really nauseous. Been sleeping literally ALL day for the past week. Feel like I'm having discharge but there's nothing in my underwear. About 3 days ago I started feeling this pain in my uterus. It was so bad that I couldn't lay down or hardly move. Now tonight I'm having a pain in the left side of my uterus. I kinda feel it in my back too. It hurts when I yawn and stretch. Going to the ER in the morning. What could this be ? Last period was 3 days late, now my next period is due Nov 24. What do I do ? What's going on ?