Should I see a Doctor?

Last week I lost my virginity to my boyfriend. We didn't use protection and I'm not on any form of birth control. The next day I experienced some discomfort and had bled a little which I know is normal. I also purchased Plan B and took it less then 24 hours later to be safe. However, my boyfriend and I ended up having sex again 5 days later (with protection)and this time I bled again. That day and the day after I bled on and off quite a bit and last night I bled a lot as if I was on my period (I should be getting my period within 8 days or so). This morning I experienced severe abdominal pains (I had been drinking the night before too) and the bleeding has already lessened a lot, but again it's on and off. I'm so confused and stressed since I'm new to all this and would really appreciate some advice and information. I'll be 18 in a couple weeks, but I don't feel comfortable telling my mom this situation, or at least not yet.