Late...

My boyfriend and I had sex 3 weeks ago and then the week after. We used a condom and he didn't cum then the next weekend he stuck it in and pulled out fast... like 1 minute. I'm now 6 days late. Last month my period came a week and a half early so I feel like it's trying to get back to normal. Ive been stressed out, lost 50 pounds. So it could change?