Late period

Hello everyone this will be long so bare with me.

I had my period last month around the end of the month. I bleed very heavy basically through clothes and even onto bed sheets when I’m sleeping. I’ve even switched pads because of it. For months I’ve been feeling exhausted on and off my periods.

I have a boyfriend we have never had sex. Sometimes we do other sexual things but we have never actually had sex yet.

I’m four days late. I took a pregnancy test just to calm my nerves because I have high anxiety and he was joking about me being pregnant even though we’ve never had sex. I took it, it was a clear negative like I thought.

I’ve had all the pms symptoms you can think of. Tender breasts, tired, aches, cravings, and bloating. I just don’t know why my period isn’t here?

What could be stopping my period?

Any advice would be appreciated! ☺️ Have a wonderful day/night (please be nice I don’t have much experience with all of this.)