6 days late, negative test at 2 days, help!?

I have not taken birth control for 3 months and I had unprotected intercourse with my boyfriend multiple times in the month of August. My last period was 7/30 and I was due to start on 8/27. I took an equate (Walmart) pregnancy test when I was 2 days late on my period and it was negative. I had already peed 4 times by noon when I took it so it was not my 1st pee of the day. Now I am 6 days late and still no sign of a period. Should I test again in a few days or is it more possible that I am just adjusting to hormones from birth control even though I've been off of it for almost 3 months?