Not pregnant?

Faith

So I’ve NEVER missed a period before or been late or anything and I’m currently a week late for my period. I’ve been experiencing a lot of things that are symptoms of pregnancy but they’re all also signs of other things so I haven’t been stressing about it or anything. But I took a pregnancy test just in case because I did have unprotected sex right before ovulation but the test came back negative. I just can’t think of anything that would be causing my late period and the nausea and exhaustion and everything else?