So confused

Alex
Since may I have had on average a 31 day cycle every time. Some months it's 32 days some it's 34. For some reason this cycle is on day 39 and I have no signs of a period coming. For about a week now I have been exhausted with absolutely no energy. The only change to my routine is my thyroid medicine dosage was increased. I have taken several different pregnancy tests and all have come back negative. I called the dr and she said the increase shouldn't affect my period. I have an apt with my Obgyn next week to see what's going on. If I'm not pregnant I will get prescribed clomid since we have been trying for over a year now. Anyone else gone through this or something like it?