Not sure what is going on

I was having cramps on left side and then started bleeding 3 days before my period was expected and I thought I was a period it only lasted 3 days but was like the same flow with my period. And that eneded and now having cramps on right side and bloated. I’m also extremely tired an dfeel like I’m sick but got tested for everything the said I DOTN have the flu or covid or strep but feel like I have the flu. What could it be?