5wks PP, bleeding has returned :(

This is a bit TMI, but I'm at a loss here. At 4wks pp I had the Nexplanon inserted as a bc method. I've had it in the past with absolutely no complaints. However, now at 5wks postpartum I'm having bright red heavy bleeding. My fiancé and I attempted to have sex this past Sunday, but stopped right away because of the pain. I've been bleeding like this ever since. I should note that I'm EBF so the odds of this being my first PP period are unlikely. Also I had a first degree tear during birth which required a few stitches.