A week late?

So my last period was the last week of December into early January. I’m intimate with my partner pretty actively . My partner is a lot older than I am and has ED so he never “finishes” when we do it. And we don’t use a condom. I was experiencing some symptoms about a week and a half after my last period and I took a test and it was negative. Now it’s been about 3 weeks after that test and I just happen to notice I haven’t gotten my period yet. I’ve also been nauseous and exhausted (but that could be the new gut health gummies I started taking and that I’ve started exercising on a more regular basis).

I’ll be testing before the end of the week but I wonder if it’s just stress? The exercising?