LMP July 18

The Chosen One ⚡️
So my last menstrual cycle was July 18. I've been to the doctor they gave me a urine test which was negative. I had them check my thyroid, which was normal. Wouldn't give me a blood test, so I went to a lab place that did give me one and it was negative too.
I'm not overly stressed out. I haven't lost or gained a bunch of weight recently. And I haven't really changed my exercising habits. 
Has anybody had something of the like happening? I am planning on making an appointment to get checked out.