Cycle day 37 bfn no AF

I am on cycle day 37 I am always regular within a day on a 28 day cycle. Every pregnancy test is negative I've took every kind lol. I feel nauseous but haven't thrown up. I was dizzy some last week. This is driving me insane when do I need to go to the Doctor I've read a bunch about hem being rude about this type of thing or just having you pee on a stick and not drawing blood. Just need some advice.