Depo provera

Any of you ladies also on the shot? I’ve been on it since I was 18 years old (I’m 24 now) and all in all no complaints. But just out of curiosity, has anyone gotten pregnant while on the shot? I don’t think I am, but I’d like to know what signs to look out for, since I’ve been on the shot for so long, my periods are basically non existent. I spot every once in a while, maybe for a few days, but then it will go away. I don’t feel nauseous or anything like that. But anyway, what are some signs to look out for while you’re on the shot?