Weird! Help!

So this is weird. I had sex multiple times in August during my fertile period. I was due for my period 2 days ago. I checked my cervix about 2 days before I was due for my period and it was low like I'm due for my period. I haven't gotten my period yet, and now my cervix is back up high. I a pregnancy test 3 days before af was due and it was a negative. I took one yesterday and it was negative. But the ones I used are the cheap ones that are just the strip and that you buy in bulk. What should I do?