Why has my personality started to change for the worse?

Hey everyone, didn't entirely know where to post this. Sorry, If I posted in the wrong area.

Long Story...

My life
Birth to Highschool: Extremely shy, insecure, awkward, low sel-esteem, had trouble holding up a conversation. etc. Extreme lonliness made me cry at night a lot.
College (before drinking): Realized there was no need to be shy anymore and everyone is friendly. I completed changed, approaching people and talking to them was almost natural and at this point in my life felt pretty good for once
College (drinking): Got drunk for the first time and felt completely changed. At this point I was extremely friendly and outgoing when intoxicated. Let me tell you that I was a very sheltered kid growing up and thought alcohol was making me outgoing and felt fake ( like it really wasn't me). Anyways, after I sobered up. Every single insecurity in my life left me instantly. I realized that I was still outgoing sober. I was considered one of the biggest flirts with all the girls in my building. At this point I felt amazing.
Currently Several Years into college: Completely lost my outgoing and friendly personality even when drunk. I honestly don't know what happened to me. Alcohol isn't really helping me out anymore. My personality is now extremely laid-back, no desire to make friends like I used. My self-esteem is like a roller coaster now. Sometimes I think I am honestly the best man that has ever been born. Sometimes I think that I am the biggest failure. I tend lose my self in day dream a lot, most of the time not realizing that I am talking to myself. Since the day dreams in my head are so vivid, I stop day dreaming either when someone looks at me funny. Experiences have little to know effect on me, even if they are high adrenaline. I'm most always like oh, cool yeah, whatever. Have trouble holding conversations again. I realized when someone I am just talking to, I just go "yeah" "cool" (giving the impression that I am not interested.

My daydreams: Note*** I am very into bodybuilding and want to achieve the best physique possible.

Most times I daydream my self as achieving my bodybuilding goal and imagine myself at parties being a stud and everyone wants me like no other. (daydream about this constantly, especially when listening to upbeat music)

Other daydreams are me imaging myself in every situation possible (can't help it). Ex: What happens if that Christie was my girlfriend? What would I do? How would I act in that situation?

How do I get my outgoing personality back?

I appreciate everyone that has read this through. I really need help.

Um. I'm not super great at helping people with things like this, but i can relate to the whole being shy and then outgoing once getting to college, and also having constant vivid daydreams. But the outgoing for me was aparently due to all the stress and excitement of starting college triggered my first super-big manic episode, which also led possibly to some sort of alter manifesting during that (I was definitely very depersonalized/dissociated for most of it), and that socialness and amazing feelings were the result. Then I got very apathetic and stuff due to depression, and now am calm and somewhat laid back due to being on proper meds, though I am now also as shy as I used to be since no mania usually.

Are you outgoing in those daydreams? If so, maybe you should try acting like you do there. You also said that you'll daydream about potentially real scenarious; maybe you should try to follow them, such as asking Christie to be your girlfriend? I know, not the best ideas, but that's all I can really think of.

Haha yeah, always super outgoing in all daydreams