So I think I'm on my period..

My period wasn't supposed to start until next Tuesday but I started with some very light bleeding Tuesday this week. Then 2 days later some werid clear with blood thick discharge. I've had some since but not a lot. Not a normal period amount. I'm pretty confused. I'm on birth control and not ttc. I posted a picture of the discharge and had a lot of people say it looks like implantation bleeding?