Help please

Okay, I need help my period usually comes down on the 10,11,12,or 14 and it never came down on any of the days. I never missed a period and this morning I had a lil pain during sex, but it could be because we didn't foreplay lol. It could be stress because I recently left work because of a policy that doesn't exist, but I would still get my period even though I stress, it would just be very painful. So, I need help if I could possibly be pregnant when can I test? Because everyone told me not to trust the app for ovulation. Basically, I can be pregnant at any time and not know. Here's a picture of the days and I took a test it look pretty negative to me.