Hello.
For the past couple of days I have been having some strange stomach pains and a constant back ache, not just in my lower back, it has been spread pretty much all over. My breasts have been sore and nipples pretty sensitive. I have had on and off headaches and extremely tired.

I just ended my period about a week ago, which was 4 days early. I am not due for my next period for another two weeks.

What could be going on?

Honestly; I feel all of those things right now. I'm pregnant. Those are common signs of the first and third trimester of pregnancy. Maybe you should see if you're pregnant? Good luck(: