Been trying for ages it feels like.

Literally Done trying if this month isn't it... Been trying for so long .. And I've tried preseed, prenatals, clear blue opks, temping, cervix checking, and cervical mucous checking . What am I doing wrong . I have a 28 day cycle. I ovulate on day 15. I don't know what's wrong. I've tried everyday and every other .. It's just really discouraging ..