About a week ago I started to bleed a little during intercourse. After it would bleed very lightly but then stop. This happened about five times. Then the last time my boyfriend and I were having sex it was very painful to even put his penis inside me, so we stopped. That was two days ago and we haven't tried having sex since. But today I started bleeding without even having intercourse and I'm not due for my period for another two week.

A few more details: 

it seems as if my cervix is swollen. I can feel it in my vagina within a fingers distance and it didn't used to be like that. It seems to be protruding.

My boyfriends penis is at least an inch or two longer than what I've ever had before and sometimes I feel it hitting my cervix if he's on top. We have had sex several times before without me bleeding.

I'm 20 years old and my boyfriend is my third partner. He was tested for any STDs 4 months ago, I was tested in the summer and my only partner after that I used condoms with every single time.

My boyfriend and I have been dating for 2 1/2 months.

I am going to make an appointment in the next day or two at planned parenthood, but I would just like to know if anyone knows the most possible causes of this.