Worried maybe

So my last period was around August 17-21. I didn't have a refill on my birth control but my boyfriend and I were sometimes having unprotected sex. I'm late on my period by 4 days now. And I'm not sure if it's because I'm not on birth control so my body is out of Wack or.... If I may be pregnant. My nipples are sore. But i don't even think that's a symptom. I am extrmly tired all the time though. And sometimes feel a little sick. But never in the morning. Always when I lay down to go to sleep.