Help I'm Confused :(

OK so I been ttc for 8 months now, and my period had been very regular but this last month wasn't, I got my period on July 25 and it lasted for 3 days, but then on August 5,6,7,8,9,10 I bleed again and it went fully away by the 12 or so. Now it's august 25, when my normal period should be, I got nothing. But I'm wondering if I could be pregnant or not, since i was bleeding lighty on my ovulation time. I took a cheap prego test and it's negative. Would it showed by now if I was? Or maybe this month is not my month since it got messed up.. Any thoughts?