Frustrated.

My husband and I have been trying for nearly 6 months. The past three months I have been convinced I was pregnant. All the symptoms I've read about. After being a week to two weeks late, my pregnancy tests STILL say negative. My period is now irregular and never has been before. I be used all kinds of apps or trackers and my projected periods and fertile window have always been wrong! Every ovulation test I take is negative. What am I doing wrong?! I feel like my body teases me and then suddenly Mother Nature gives me my unwelcomed gift. Was is my period slowly going from 28 days apart to now 37 days apart?!