Painful sex bleeding afterwards..... help?

[Goolia]

I'm 22, I've been with my partner for almost a year now and a few months ago sex started becoming painful. It hurts just inside, its not a stinging or a burning pain, and hurts primarily on entry. However sometimes, the sex will start to feel great after entry but then starts to hurt again after 10min or so. It feels as if the pain is roughly around the area of my G-spot. Basically if i tilt my pelvis upwards on entry it doesn't hurt as much but still hurts a fair bit. My boyfriend doesn't have a gigantic penis but on entry it feels almost as if my vagina just doesn't want to stretch and its being forced open. I've never had this problem before. After a while I started to get a tiny bit of blood after sex, just a little pink smear on toilet paper, so I didn't take much notice. As the months have gone by there is steadily more and more blood, and now I dont need toilet paper to notice, my boyfriend can see it and its bright red. We dont have rough sex so its not that, its not an arousal issue cos I'm almost always in the mood. I have made an appointment with a gynaecologist but I'm freaking out a little. I've been tested for STDs and I dont have any, I've just gone off the nuvaring cos of mood swings and i assumed it was causing painful sex. Does anyone have any idea what can cause this? I feel horrible cos my boyfriend feels upset every time cos hes scared hes hurting me.