Insecurities

Hi girls, I’m only 16 but I’ve had some relationships and I ended up being cheated on in all of them. Because of that, every time that I start to talk to someone I start to question myself whether that person is going to do the same as the others. I start overthinking a lot and I create all of these crazy scenarios in my mind. I’m also very reserved and I tend to keep my feelings to myself. I just want to know, how do I get over this. I really wanna try and trust someone but every time I do that the outcome it’s the same :(