HELP!

Ok, so I was having sex with my boyfriend and everything was going fine but when he started to finger be I started to bleed a lot and it's not regular period blood and I got so scared because I've never seen such a thing and it was quite a large amount. I wanna go to a gynecologist but I'm 18, my mom is a crazy Christian and my boyfriend is 16, so if she knows about this I will get kicked out or she'll never allow me to see my boyfriend again. I can't just tell her I'm going to the gynecologist cause she'll know something's up.