I Had Sex With My Boyfriend For The First Time.

I had sex with my boyfriend for the first time. Penetration was pretty deep. At one point, I specifically felt like his penis hit something and it took my breath away. We stopped for a few moments, and when we started again, the pain was less if I held my stomach tight. However, at one point we noticed blood on the floor. Now, I have a deep pain , almost like menstrual cramps. I am 42 years old and on birth control. My last period ended on Sunday of last week. I plan to call my OBGYN on Monday, but I'm concerned.