Break through bleeding? Miscarriage?

So, this cycle has been weird. At 14DPO I have no PMS symptoms and was experiencing weird caffeine sensitivity. At 16 DPO, I tested and it was negative. Later that day, I started what I thought was my period but I didn't have any serious cramps. Now, a week later, I just got a positive pregnancy test (I tested because I'm exhausted). The thing is, I'm still bleeding lightly. There's no cramps or anything, and I'm not wearing a liner or tampon but there's still some brownish blood. There's no clots but I'm not sure what to think?

Normally my periods last about 3 days. This past week. I had 2 days of flow and the. Bled on and off. I took a pregnancy test as a fluke. It doesn't make sense. I had negatives before!