My period was due on May 1st or May 2nd and I have yet to receive it. I experienced some spotting around my ovulation time (not sure if it was during ovulation or right before.) It occurred April 16-18.

I did have unprotected sex (pull out method--yes i know, stupid) a few times this month. After I experienced the spotting, I was worried that I could be pregnant.

I took a pregnancy test on April 24 and it was negative, but I figured that it may be too soon to tell. I took another one on April 28 and it was also negative. I took one again today that was negative as well.

I am assuming that at this point I am not pregnant and that my late period is due to stress from finishing up school and this pregnancy scare.

What are the chances that I am still pregnant despite 3 negative pregnancy tests? Should I take another one?