I’m 4 days late on my period. I’m never late, always on time so this has never happened.. I always feel when my period is about to come and I’ve been getting cramps here and there but no blood at all.

I took 2 first response tests last night before bed and both were negative.

Is there a chance I tested too early and I could still be pregnant? I attached a pic below of when I had unprotected sex last month (red hearts) and I was suppose to get my period on September 5th. Also I think my ovulation is not accurate on the app so I’m not sure when I ovulated or if it could be correct of when I did.