Vent kinda (possible trigger warning)

So I used to date this one girl but she got over possessive and would stalk my posts and like every post and comment on everything thing I did and she would say stuff like I was perfect and amazing and it was nice at first but it just started getting creepy so I ended her and i relationship and had to block her (it wasn't on this app)
So sometimes if I find someone whos profile is completely blank and the only person there following is me and most of the only stuff there liking are my stuff I get terrified and I end up blocking that person

Uhm that's happened twice on this app and those two people might have been nice people but Im just scared and ever since then I've been paranoid for 4 years so uh yeah any advice?