My period is unusually late.

For the longest time up until I turned 22 my periods were irregular. I would have one ever 2 months or so. When I turned 22 my periods became constant. Every month I would have one. Up until this year around February (when trying to conceive) I did not have a period in March but I had one in April. We tried again to conceive in April as well. I did not have a period in May but I have negative pregnancy test. It is now June and I am over 40 days late on my period with negative test still. I have tried everything from working out, drinking more water, eating healthy, ect. I went to my OBGYN and they found nothing alarming. Why is my period late and how can I start it so I can continue my TTC journey. I feel helpless and lost