Sex,confused

So I was on the depo shot only had one dose of it, haven’t really gotten my period yet since I’ve been off it besides one time which was in November. But just this past Saturday on the 5th my boyfriend and I had sex, yesterday I went to the bathroom when I wiped there was blood not a big amount so I thought I was going to start my period but there is no more blood now. Idk what is going on.