AF is acting weird!

Sarah
I am due to start AF tomorrow the 27tg, however i have been spotting since the 19th. I took a test 2 weeks ago because i was having a lot of nausea and got a BFN! Scared to take another test. Tired of seeing Negative. My hubby and i been TTC for 3 years. Doctor says everything good with both us! Any insight ladies?