Help me

Kaytlin • Bisexual 🏳️‍🌈 Suicide survivor 💋 Bipolar sufferer:(:

So I had sex January 8th, he didn’t finish or anything but idk if there was pre cum. Anyway I got my period shortly after. But this month I’m waaaaay late. I’ve been bloated and hungry, I’ve had extreme mood swings and I’ve nauseous. I though I was pregnant but i never told my mom, i got a test and took it, it was negative. But now my moms thinking I’m pregnant and I can’t tell her I’ve already took s test. I don’t think I’m pregnant bcuz of the following reasons, 1: the test was negative, 2: my periods never regular so it’s normal for me to miss months 3: my period could be late because of me stressing, not eating right and practically never drinking water 4: I always have mood swings, I’m on new mood stabilizers but obviously they haven’t been working, and 5: the new meds I’m on make me eat which is why I’m always hungry. What do you guys think I should do?