Late period and BFN

Abbey • 27 years old. Married for 1 year trying to conceive baby #1.
 I am feeling so frustrated I am currently on cd 36 and no period and 2 negative pregnancy tests. Short background: quit bc 1 year ago had irregular periods. Been ttc since December 2013. In November my dr put me on provera to start my period. Had 3 regular 25 day cycles then they put me on metformin my last cycle was 32 days. I just wish I knew what was going on.