How early is too early to test for pregnancy

I took a pregnancy test last week (because I stay paranoid) and it was negative. My boyfriend and I had unprotected sex after me missing a pill almost 3 weeks ago. Idk if I’m pregnant or not but I’ve never experienced this kind of nausea, mood swings, irritability, and overall just feeling horrible. I don’t have the flu and I’m not sick. I just don’t want to waste a test by testing too early. So how early is too early for a home pregnancy test?