I was 3 days late for my period. My boobs started feeling sorer than usual and a little more veiny, Ive been having to use the bathroom more frequently, and this is the first time I've felt this nauseous before a period. I had unprotected sex about a week before my expected period which is(03/20/17). Today, now the 23rd I started have cramps but not near as bad as they usually are, accompanied by some bright red blood. Could I still be pregnant?

Unlikely that you're pregnant if you've gotten your period. Three days late, when it comes to pregnancy, is not even considered to be late, and many women are 3 days late or later without being pregnant. Late periods happen to all women at one point or another, and having experienced them rarely in my life, when it was just a late period, it was an odd period once I got it. Either a lot of blood, more than usual, or barely any bleeding at all. Lots of fun trying to figure out what's going on.

Now, having said that, is it possible that you are pregnant and just experiencing bleeding? Yes, but it's unlikely. Is it possible that you were pregnant and are experiencing an early miscarriage? Yes, but sadly there's no way for us to know if that's happening, your doctor may not even be able to tell for sure.

The most likely cause is that you're just having an off month, possibly nervous about the possibility of being pregnant after having unprotected sex, and it threw off your period. It happens all the time.

Now, all of the info given, can't replace a doctor if you're worried about this. All we can do is tell you possibilities, we can't diagnose, not even a doctor can diagnose online and there are no doctors on this site or any other, because no doctor would risk his/her medical license by diagnosing people online.

If you feel this period is off and pregnancy is possible, wait for your next period. If you miss it, then try a pregnancy test using first morning urine. If you don't miss it, then you have your answer. At this point in time, a bit more than a week since unprotected sex, it's way too early to test.