Could I be pregnant

My period is normal for the most part but in May it came the 16 and June it came the 10 but this month I haven’t gotten it I took a test the 10 but nothing. I had sex but I got something that I thought was my period but only lasted a few hours and it was heavy then nonexistent. I haven’t had it this month I was sexually active around the time it was supposed to come but now I’m feeling constant tiring after I eat certain things I feel nauseous and I’m having headaches and cramps like I’m on my period