Ovulation bleeding?

So I had a very clear positive on an OPK on Saturday. That day I started having a brownish blood, but very little. The next day it was more reddish brown and even had two tiny blood boots in it. It was enough that I used a pad, didn’t come close to filling the pad tho. Well now I’m going on day four of having that brown blood spotting. Any suggestions as to what it could be??