Late AF

I need some advice, AF is late (very rare) I am now on cycle day 37. My cycle varies from 30-32 days max. I have been having slight abdominal twinge for a week now and extremely tired to the point of having to sleep in the afternoon. No usual symptoms of AF coming such as cramps. I tested with a first response at 13dpo which was negative and a clear blue dye test yesterday which had a very very faint line after about 15 mins. I discarded the test as I know they are bad for giving evap lines. Does anyone have any advice or a similar story I am about 16-17 dpo confirmed with opk and temping. Thanks a lot x