I've become antisocial

The level of my social skills was at its peak in the year 2009. I spoke to a lot of people I didn't know and became friends with them. I went out every weekend and did something fun. I went to parties and enjoyed it. Back then, my circle of friends was so huge, yet I put in the effort to text everybody and stayed close with them all.

These days though, it's been really hard to put in the effort. I go town maybe once a month? I go because I feel that staying at home all the time is bad for me, yet when I'm in town, I get bored and go home early. What's wrong with me? Swear down I've changed, but I don't even know why. My mom used to tell me off for coming back home late, usually at 11pm-1am, now she's asking me why I come home so early. I try my best to reply to people's texts and messages but my brain just can't get into gear.

This worries me because I'm going to university next year, and I need my social skills back. I don't wanna be some loser in the corner who isolates himself.

I wish I was more social.