Period confusion

Hello !!

My period has been all over the place and I am wondering how can i distinguish from “spotting” vs a “period” if my regular period is very short and light in general. If I count it based on consecutive bleeding days this is my 3rd “period” in 29 days …. For context I am TTC and went off of depo provera my last shot was in may so as of August it would’ve worn off