Emotional as hell!

Im on day 13 of my cycle and I can't stop crying about an argument I had with my bf last night it's not that huge of a deal but I keep bawling everytime i think about it! I woke up crying , the problem being the first thing I thought about as i woke up. Is this symptoms if pms or pregnancy or is it just my emotions getting the best if me, and I'm taking the situation more serious than it needs to be? Please help