Attachment issues. Please help

I've been in a long distance relationship for a year and a half now. He is such a nice boy, so caring and sweet, and i think i am the problem in our relationship. He has a work and i'm still studying (i have one year of university left), so i actually have a lot of free time and I'm also an overthinker with self esteem and anxiety problems (diagnosed). Since he's always at work, we only talk in the evenings on weekdays and I feel so anxious about not having more time with him. Tonight he is gonna be out and, I don't know, when he told me this yesterday i freaked out and broke up with him. I know that i'm so immature, i really wanna heal, please give me advice, i can't go to therapy right now. When we are together in real life, things are so good, but we can meet only once a month and in the meantime we always fight because of me