3 Dys Before Period Due Had L/brown Slight Staining. Then

3 dys before period due had L/brown slight staining. Then on evening of day period due got dark brown light to medium period that petered out by 2nd day. Nothing more unless I wipe for the third day off and on and then nothing more. My periods normally last 5-7 days and are usually heavy and red. I am ttc and recently got diagnosed with possible pre poly cystic ovaries. Could I be pregnant or is this from my ovaries? Got a bfn when I tested on the day the blood disappeared.