Controlling emotions

I can't seem to control my emotions at all and it is really obvious and acting up my paranoia that others can see it. Like I broke up with the only guy I love because at college there was someone who is like him a lot and I got feelings for him and we weren't really talking so I was missing the interaction that we had and I tried to get him back and obviously he can't see a future with me again. This all because I got swaded and it just took control over my mind and I have no clue how to control these emotions to stop this happening in the future. Please help😭