Implantation Bleeding?

I'm 34 been TTC #1. Supposed to get my period on Wed, Jan 13. Very high likelihood that I'm pregnant as we used Clear Blue Digital Ovulation Predictor and BD on our high peak day. The last two weeks I've had really sore, tender, enlarged breasts. Today I had what I think is implantation bleeding - it was a red blood and now a brown discharge and I had one jelly like clot. I'm so scared as this is the first time I've gone through this. Have any ladies out there had implantation bleeding 4 days before their period like this and then been pregnant?