What is happening! ?

I am on CD 51! My cycles are normally 35 to 37 days longer than normal but consistent. Last AF was Aug 26. AF should have came October 2nd and never showed. I have been nauseous randomly throughout the day every day and can barely eat the foods I used to because it either makes me feel sick or the thought of food makes me sick. I've taken multiple tests and they all come out negative. This is all confusing.