I Got My Period Last Month Right On Time. Had

I got my period last month right on time. Had heavy bleeding for two days and then on third day I started coming down with flu and my period just shut off and only had some spotting and it wasn't like I was deathly ill. So now my period is due in four days and I have no pms symptoms just tons of gushing discharge,low back ache and leg aches and some fatigue but I figured there's no way I can be pregnant because I did bleed heavy for two days so I'm confused