Do you have trouble relaxing at the start of intercourse as well?? I'm in the US we have planned parenthood for people without insurance, do you have anything like that. If your nervous and clenching up during intercourse this could be the problem. I would keep trying doctors if this continues...Sorry, I don't have any real answers.
I TRIED LUBRICATION B4 BUT NOTHING WRKED ND I NEVER SAW THE USE OF IT BEING DAT IM NEVER DRY...ALTHOUGH ITS VERII HARD 4 ME TO GET EXAMINED BECAZ DA DOCTOR WLD ALWAIS SAY I DNT RELAX MY MUSCLES ENOUGH...I FEEL KINDA WEIRD SAYING IT BUT I GET WET EASILY SOO I WASNT SURE IF ME BEIN TOO DRY WAS THE ISSUE I THINK ITS MORE OF A COMFORT THING LIKE I JUS DNT FEEL COMFORTABLE ROUND NE DOCTOR 4 ME TO EVEN LOOSEN UP...ITS LIKE A MINDSTATE THING ND ITS VERII ANNOYING BUT I KANT HELP IT && 1 TYME DA DOCTOR FORCED IT IN WHICH CAUSED ME TO BLEED DAT 1 TYME AT THE DOCTORS OFFICE BUT UMM IDK WAT THE PROBLEM IS && NO DOCTOR SEEMS TO GIVE ME ANY ANSWERS
If it's only happening during sex it could just be from lack of lubrication. Have you tried using a lubricant this would cut down on the friction. If it's too dry you can get small tears in your vaginal wall.
Oh I'm sorry I mis read your post I thought you'd had an IUD. Please disregard my above statements.
While all your tests came back negative, did they check your IUD to make sure it's placed correctly. It could be that when you're having sex, your IUD isn't placed correctly and it's sraping your uterine wall during sex causing you to bleed. Planned Parenthood should be able to set you up with an OB/GYN that will take a small fee.