Weird period?!

I had my son almost 2 months ago. My postpartum period lasted for a full month, it ended for a week, then my first period came back. I’m now on day 15 😩 usually my periods last anywhere from 8-10 days but never this long. TMI but I also have a weird thick brown stringy discharge as well. Anyone know what this could be??

Also, I haven’t had sex since I’ve had my son so that’s not it & because of that, I’m also not pregnant so I know that can’t be it either.