Ttc. Heavy dark brown spotting during ovulation??

I've been ttc for about a month now. According to this app i should be ovulating right now. I'm exactly in the middle of periods right now and I've never spotted before. It was strange because last night i noticed a little dark brown spot on my panties and so i stuck my finger up my cooch in the shower and it was brown and tacky-ish. This morning i ended up putting a tampon in because it seemed a little more than spotting. Now tonight it's just barely spotting again. Anyone have any ideas what could be going on? I'm kind of nervous here.