Looking for some answers about pregnancy and hormones.

So about the first week in Jan I got a 4 day period instead of a 7 day liek it usually is. Then about a 4 days after my period i had light spotting for 3 days. I just ended then pill before i got my period. I was in the process of moving so I couldnt refill my prescription yet. So I moved and I havent gotten my period since the first week in Jan it is now the 3rd week in Feb. I have never experienced late and non existent periods before they are always on time. It wasnt the fist time Id taken a break from the pill I ws off it for 2 months last summer. I had only taken it for about 4 months before that. So now I am late and my boobs get real huge in the morning and my nipples HURT constantly. Also the last few day I have felt crampy like Im going to get my period and nothing. What could be going on? Hormone imbalance? Pregnancy?