TMI no picture. Need advice

Rebecca

Maybe a bit TMI

From early hours of Monday morning til late last night I had brown spotting. It was like old blood. But I haven't had AF since 18/4/15 according to my calendar I am 16 days late but when I went and seen my fertility doctor 2 weeks ago I was told I wasn't ovulating. I did a hpt on Tuesday with FMU and was negative.

I'm obese and also have a thyroid problem but levels are normal and on medication.

What else could it be?