Confused? Can it be implantation?

My husband and I are currently TTC for about the past 8 months... I have PCOS so things are a bit complicated. This month however my period really never had a flow start for about 4 days now I've had some light pink and brown spotting. I've read a ton of articles saying implantation normally is a couple days at best? Just not sure what's going on .. if it's hormonal inbalance the Femara treatment... or could we finally have a bun in the oven. If anyone has experienced this and can shed some light would be greatly appreciated.