Plan B while on Nexplanon

Hello!

TMI possibly but trying to give accurate info.

I am on the Nexplanon implant, it’s about 2.5 years old.

I had unprotected sex April 28th. Ovulation predictor predicted ovulation around 4.17. I took 2 plan B after, as I’m a plus size woman. I had bleeding for 7 days starting 5.4. Bright red, heavy, some clots etc.

My period is predicted to start today. I took a pregnancy test Sunday evening and it was negative.

Is there any chance I’m pregnant?