So supposedly sex and masturbating aren't supposed to affect your period (at least that's what I've read) but it seems like it does affect mine...?

It seems like when I have sex or masturbate by fingering myself it sometimes triggers my period. Like right now I was like 3 days late and then I had phone sex with my bf and when I went to wash up, I was bleeding. I'm not in any sort of pain so I don't feel like it's because I hurt myself. And this has been a thing for like almost 3 years. I don't always bleed, it's just sometimes. Idk y'all. What do you think? I know I should ask my gyno about this and I plan to. But I figured I could get some input from y'all in the meantime