How to get my social skills back? And more..

Hello, I’m 24M.. Edit: if you don’t want to read the whole thing just read the last paragraph.

Ever since I entered adolescence I’ve always thought I’m bad socially, but looking back I was wrong and it was all in my head. Cause at the stage I’m at now it is drastically worse than before. I’ll try to minimise my story as much as I can.

I used to be loud and talkative around people, extroverted, so I was able to easily connect with people around me from the first week or less and they usually say “I feel like I’ve known you for ages”

Now in my first and second year in college I met people that I like hanging out with and they liked hanging out with me too, we’d invite each other to go out and it was all going well. The story involves two people, one I like hanging out with cause he’s fun and very social with people I’ll call him N, he loved hanging out with me too, and one who was my best friend at the time A. I never shared my thoughts about that I believe I have bad social skills to N cause he’s close but not as close for me to share these issues, I shared them with A though.

In my third year, A started reading books about developing social skills, and he started telling me that I’m bad socially, I act childish, people don’t love hanging out with me, over and over so I unfortunately believed him and it started becoming more true over time because I believed it and he even became distance. So I had no choice but to cut out A, cause a friend should help you not put you down so I ended without looking back. However with N, he also became distant for some reason, when I asked him he said I don’t want you to get mad but I think you’re becoming slightly clingy, and I respect him for telling me but it did hurt. So I stopped contacting him as well and stopped socialising with people because what A kept saying affected my mental health and gave me social anxiety.

Now after a year, my social anxiety is gone but so is my social skills, I’m became more of a calm, quiet person, un-interesting, and people just hang around with me just because they have to not because they want to. I saw N with his friends group by chance two days ago and we hung out together, I invited them over and we had food and before they left they said we’re going to another city tomorrow want to join? I said sure. Tomorrow came and they didn’t call and I see on social media they went. I wasn’t mad because that was expected since last year he was distant and not inviting me or anything. Also I don’t actually blame him because when we met two days ago I was boring and did not bring anything fun to the table to be fair. Even my old self wouldn’t hang out with me now and I know it! So what can I do, I do want to bring the lively person back when I meet people but I just can’t, I feel empty and have no specific interest I can talk about, and also I’m afraid people see me as childish.