How can I learn to handle my emotions?

Im in a relationship and found myself getting overly emotional and anxious. I’m scared of him cheating or falling out of love with me, and even since we had gone long distance for college I have constant gotten upset,jealous, anxious, and overly controlling throughout the school year. Like for example: he started to drink alcohol at his fraternity and I freaked out over it because I thought he would become an alcoholic or drink too much and cheat on me, I was also jealous that I wasn’t able to be there with him as much as his friends at college. And I would get jealous of upset if he hung out with his friends over me. But just to be clear: he has done literally nothing to make me have these anxiety and worries or fear. He makes a lot of time for me, always would reassure me, never has done anything to make me thing he would be unfaithful, and always want to talk to me. I don’t understand why I’ve become this overly emotional mess who will get trigger anf blow up at him if he doesn’t maintain our routine or if he does something that makes me upset for no reason. We have been together for a year and nine months and I really love him, but I just hate the person I am. I’ve caused a lot of fights between us and it’s taken a toll on him. I feel like he’s become less affectionate, and he’s admitted that he tries to be a better boyfriend but feels like he’s not enough. I love him and hate how the relationship feels because of me. Can someone please help me find ways to keep myself under control? I went to talk to a counselor in the spring but sessions with her were more ranting and it was hard still to learn things tk keep myself from blowing up on my boyfriend. I just don’t want to feel so miserable anymore and bring my boyfriend down with me.