HELP!!

So back in January I had my regular period on the 24th. I have pretty regular periods either around the 24th or the 4th of the months. They dont track too far away from those two dates. That being said February I had very pale pink spotting (not enough to use pads/tampons) and had one positive test multiple negatives. Ok, so waiting for March to see if that period comes so I can retest. NOPE, same thing as in February. I test and get one positive, multiple negatives. I must add I dont not feel pregnant nor do I think I'm pregnant. What else could cause this? I do have pcos but a very mild form, havent had any problems since I was 15 and regular periods for over 10 years. Any ideas?