Flu or pregnant?

My last period was March 3-7, the weekend of March 16-17 my boyfriend and I had unprotected sex & my period was supposed to come on sometime last week. I have been feeling really tired, really bad back pains, extremely nausea, cramps for about 2 weeks straight. When I thought my period was coming I started breaking out which happens normally around when my period comes but then it went away still no period and for this week, I’ve been having chills and a fever and feeling really bad. So yesterday I took an pregnancy test two came in the box but the digital one didn’t come on and the second one was negative but I still feel kind of off. Maybe it’s from stress? I’m a college student and really scared rn. Could I possibly have the flu or be pregnant?