When I was in elementary school I became friends with lots of the other students in my class quite naturally, like most people do at that age.
This then also made it easy for me to get a stable group of friends, and some of my best memories are from around junior high school when I was 13-16 years old.
That was the time when I had several friends that I hung out with in my free time, and I always had at least like 3-4 friends at school that I always spent time with, and this was definitely extremely energizing and made me a very spontaneous and confident person in general - I didn't even have any problems making eye contact with cute girls and smiling at them, that was just exciting and fun.
I have lots of memories of really good times when I was fooling around and being spontaneous in general with my friends back then, and I even have several memories of moments when I experience pure exhilaration just because I thought my life was so awesome, and this strongly indicates that I really did feel great back then.
However, in high school I started losing contact with lots of my old friends, and ever since then it has been really hard to "get back" to how it used to be.
Basically, I became more and more careful around people and started to become more and more of a loner, although I do still sporadically meet 1-2 of my old friends, but it's only a coupl times a year or something like that.
Now I have studied an engineering physics program at university about 500 miles from home for a couple years, and even though my new classmates seemed to like me in the beginning they noticed that I was fairly careful and quiet (basically, I never approached them myself and I didn't talk that much, even though I tried to be friendly when I spoke to them) and then gradually became more and more nervous around me, and now they look really insecure and uneasy when they see me at the campus and say "...hi" with some effort.
And this also makes me feel more on my guard as well, since I am worried that my own approaches will just fail from now on or something.
This has also made it really hard for me to make eye contact with girls as well, because everything simply feels so serious - I don't feel that casual excitement, I just feel stiff and awkward.
And sometimes when I think back on my best social experiences from my teenage years, it has such as impact on me that I actually start crying, because I really wish that I could regain that personality that I had back then.
What do you think that I should do?
I don't know where I should start, because it would feel weird if I just randomly entered a conversation with them somewhere at school when they had already been friends for a long time.
I have considered going to one of the night clubs or parties at my university and see what happens there, but I feel that have a lot of expectations on myself and that I immediately must make the same positive impression on people like I did naturally back when I had my confident personality, even though I realise that I shouldn't think that way.