Sex and Bleeding

Me and my partner had sex end of January for the first time which was a little painful but nothing major , then again start of February once again “normal” no problems

Then this next time was different , it started off normal, but we tried a new position this time and I bled , not just a few spots , it was a lot.. , I’m just confused as I haven’t bled before , have no infections.. does anyone know what could have caused this.