Is this implantation bleeding or no?

So I was supposed to get my period today. Which I did around noon. It was bright tee and orange but really light. So I thought it would pick up later in the day and it hasn't. In fact..: it's actually stopped? I can't tell if I'm just about to officially start tomorrow or if this is a sign of pregnancy? I'm on birth control and have been for over 4 years. I take it religiously and have never missed a pill. I guess I'm just worried something is not right. Is this normal? Will my period pick up more tomorrow? Any advice/suggestions would be great!!!