Late and negative

So I'll start off by saying I'm not one to post much, but I'm not really sure what's going on with me. I'm usually clockwork with my cycles...28 days. I stopped doing OPKs because they were consistently on the same day and the constant testing was stressing me out. I started taking Ovaboost this last month only because I'm 35... all of the testing I've done at Dr's office have come back normal. Now I'm on CD 37 and no sign of AF and I've taken 3 pregnancy tests (3 days late, 6 days late and today) and all have come back negative. Has anyone had something similar? Could Ovaboost be causing this?