I bleed almost everytime I have sex with my bf...is he hitting my cervix?

I am a 36 year old woman and I have a 26 year old bf...no cougar comments please. He is very well endowed which I thought was a great thing but almost everytime we have sex I end up bleeding...sometimes alot, sometimes a little. I have seen my Gyno and she ensures me that it's normal but then again she's in and out in 5 minutes. I've never had this problem in my life. We do try different positions so he is not so deep (it also hurts sometimes but kind of a pleasure pain) but it doesn't seem to matter. I am always "lubed up" so I know it's not a dryness issue. Does anybody have any ideas or suggetsions?