Periods post baby??? Need advice! Probably TMI

My dd is 9 months old and I breastfed. Around 4 months we started supplementing because my supply was low and my periods came back. Since then they have been between 30 and 37 days apart which is fairly regular for me! But I bleed mid cycle almost every month. It seems to be because of ovulation because it's always the day I'm supposed to ovulate or the day after. But this month I have been bleeding since the 6th. My period is due anywhere between the 20th and 27th but if the bleeding started around ovulation it should be the 20th. It's on and off but fairly regular. It goes from dark brown and jelly like (sorry, I know that's gross) to bright red randomly and there have been multiple clots.

We plan on trying for #2 in August but really am hoping I am not pregnant (for one, it doesn't seem very healthy if I am. And two, I start my externship for school in August and will likely not graduate if I have to take 6 weeks off of my externship in January/February.

I have been incredibly stressed because of school and finals which have been over for a week, quitting my job to be a SAHM (financial stress), and my best friend leaving the country to study abroad for a month, and I my dd and I both have a cold. But I'm really curious to hear other experiences or opinions. I have a pack of pregnancy tests and they have been negative. But I am waiting a few more days before I try again.