First trimester discharge?

Yesterday I started bleeding and went to the er. Doctor said I had no active bleeding. He did an exam and I had an ultrasound. Everything with baby is okay (I'm about 7weeks) I was diagnosed with threatened miscarriage and a mild uti. My bleeding stopped. This morning I went pee and every time I wipe I get little brown specks of discharge. I've never had this before.. Was wondering if anyone else has? Is it old blood? Why is it in small little chunks?