Ruined relationship

Hello, I don't really know what to put down but I've been feeling bad about some decisions I made in the past and how they haunt me.

When I was 16 (3 years ago) I had met an old acquaintance of mine from elementary school, in high-school, I was always really into her and we started talking and became just friends, she would text me goodmorning everyday and send me a goodnight message every night, I developed a connection to her and I wanted more from our relationship but she didn't feel that way but kind of refused to express it, after I had divulged my feelings and she soft rejected me (didn't outright say it) it made me feel small and lesser of a person because of insecurities I had prior and the way it all played out just reinforced those. About 5 months later after me and her drifted apart and came back together as somewhat friends but, not like it was before, I still had very strong feelings for her and in a state of desperation to get away from what I felt I asked my other friend who's dad would buy him liquor, to buy me some. I payed $40 and got a 1.5 litre of baccardis and drank it all in 3 days, then I bought another, and another.

During this drinking I decided to start texting this girl and having interactions with her I can hardly remember, it got to the point where I would text her mean stuff about her and her boyfriend at the time andthen apologize to her the next day and say I'll never bother her again, and then I'd drink and text her. It happened enough times to where I will never see or talk to this person again for the rest of my life. I'm 19 now and I still can't go a day without thinking about how I absolutely decimated a relationship with someone who made me feel like an actual person who deserved love.

It is all my fault, and only my fault and I will always be less for what I did to my most cherished friendship.