Bleeding during sex

I just had sex with my bf and I was bleeding. What does that mean? I already had sex before with other guy and nothing happened. I'm so scared like should I be worried? This might seem stupid but this time the penetration was deeper and I don't know if has anything to due with that.... I did some research and the causes for bleeding during sex were mainly infections but I feel completely fine. I don't talk bout this with my mom she doesn't even know that I'm not a virgin. Should I talk to her to see a doctor or am I just over reacting? Please help me