Heavier periods after missed miscarriage

I had a missed miscarriage so after my surgery which was almost 3 months ago!

I’ve noticed that since then my periods have been coming every 2 weeks instead of when i used to get it which was every 4 weeks. It’s also been way heavier with lots of clotting and cramping..

I don’t use protection either and I can’t seem to get pregnant again :/

Is there maybe something wrong..