What Causes Breast Soreness And Gagging?

I'm not the type who keeps track of her period and how it works or anything but I do know when its about time for it to start. This week it seems I've started a week or 2 earlier then usual. I could be wrong. That's not the problem. The period only lasted 3 days. It started off light that I didn't even notice it at first. The next day it was kinda medium bleeding and then it became light and just stop last night. The color was a normal red. Its morning here where I am now. I am sexually active. My bf and I were together (protected) on Friday. The period started on Monday and ended yesterday last night on Wednesday. My cramps were a bit sharp and I took Midol for them (Monday and Wednesday). My breast have been sore and they seem to be or look a bit different. I woke up this morning and felt like I gagged a little but it felt like a dream. I'm not sure. Could this probably be due to stress or depression? Any help would be appreciated. Thanks. I'm 23 about 141 lbs and 5'6. Last visit that I had to my doctor was about a year ago for my pap smear.