How to deal with myself for how I am?

I’m suffering a lot because I’m 21 and I never had friends and spend most time alone in my room . I have accepted this but the issue is that whenever someone comes along and gives me a chance to get to know me , I feel as if I’m a full water bottle who finally had its cap taken off and all my emotions just flow out making me quite impulse, talking excessively , saying things I regret etc and it also does not help that I have a very strong distinctive accent . Then that person ends up leaving me too and I’m alone again . I have so much regret and hatred to myself because I keep working to change myself and become more controlled in conversation but for some reason I keep failing and failing and I feel so lost and like there’s no hope . Sometimes I wonder whether it is because of this or whether it’s just because I keep meeting the wrong people not for me ?

Why, at 21, are you staying in your room? Do you have a condition that keeps you home; why aren't you studying or working?
You don't have to answer in detail; I'm just trying to get more context.

I’m at university . I commute but because of lack of friends , things to do I’m in my room most of the time

So what have you done to meet people in a controlled environment where there's subjects to focus on for conversation; sports, societies, church, volunteering, part-time job?