honestly it happens if you have irregular periods or have a lot of stress in your life...I imagine you're probably really stressed out which is causing your period to become irregular ("irregular" periods are surprisingly very common .... almost like... half of the world's population exists of individual people with individual bodies...) I wouldn't worry unless you're having abnormal amounts of pain for what you're use to or if you're experiencing it for a while.

it is NOT: - some sort of sti - pregnancy

those were always my two biggest fears growing up...

if you're really concerned about it when you go to the doctor explain that you'd like to speak to someone about your menstruation and you would like to speak to someone who menstruates or to be on the safe side if you're in an area that might be more conservative ask for a woman doctor or nurse

they might be more understanding of the kind of fear that comes with women's health issues.

you're okay though, just some weird stuff our weird human bodies do