Am I doing it completely wrong? (sex)

Ladies I have a serious question about sex. A couple of months ago I noticed as if I was extremely tight down there. Whenever I would have sex with a guy, it would hurt and I would sometimes bleed. They would also tell me how crazy tight I was.

About a year ago when I lost my virginity there were no issues what so ever. Big and small penis sizes.

Fast forward to now. I just recently got into a relationship and we have had sex 7 times so far. Every time we have sex we can only do missionary because sitting on him hurts me AND him. We also tried lube but I am so terribly tight. I am so sad about it. I recently got and IUD inserted at the gyno and they said everything down there was fine.

So my question is; is there ANYTHING I can do??

Please help me. I’m extremely worried about this