Me and my boyfriend had protected sex yesterday (6/4/16) and we had sex twice. After the second time, I began to bleed but not much. This morning however (6/5/16) I'm bleeding as if I am on my period even though I'm not due for another 2 weeks. My breasts are also very very sensitive, especially my right one and more the nipple. Please help me understand why this is happening? I'm 19 years old and I don't know if I should be concerned or not.