Is there a possibility I’m pregnant?

So i didn’t have a period in June, but ended up having one on July 4th... I had sex July 22,23, and the 25th (22 being ovulation I believe) later on that night the cum didn’t come out til 2hrs later and ever since then I’ve been having constant headaches, off and on mild cramping, and cravings... I’m not suppose to start my period til a couple more days but I ended up taking a test which was negative... is there still a possibility I’m pregnant?? And I’m just testing to soon or what?.... my mom has been feeling sick to her stomach the past 2 days as well (not sure if that’s related to me or what)....