Top level high school runner...feel like a loser

This is a great answer! Also when you see friends doing things without you, ask them if you can go along next time. They might think you're too busy for them or not interested because you haven't been before. You can tell the truth and say, "I want to have some fun too. I'm tired of being thought of as the one-dimensional running guy." Lots of things in life are hard and take some effort. Running for you comes naturally. Sounds like socializing is not as easy for you, so you'll have to work at it and put in some effort. Also, be patient. Even if you ask to tag along or invite people to do things with you, it make take a few times before it people start to say yes. And it may take a while before things start to click.

older guy here wrote:

Just a suggestion, but instead of waiting to be invited to do stuff, maybe think of something you want to do and invite others to do it with you. I know that it's not the same, but if you're true goal is to do stuff with other people, that's a possible option.

If what you really want is to be "wanted," to be invited by other people... totally reasonable feeling... but then your happiness is in the hands of others so it's definitely a hit and miss kind of thing.

Go to a decent D3. You will go to some decent races, have a fun team, and have plenty of opportunities to party with your teammates.

First, high school can be tough regardless of your sport. Running is likely not to blame. If you enjoy it, keep doing it; it will give you so much more in life that you will gain by quitting. I don't recommend drinking until later in life, anyway, but running is not likely what is preventing you from the social life you want. Hang in there and let yourself grow up a bit. You will be more sure of yourself before you know it.

As for continuing in college, being on the XC and track teams in college was the best part of my college experience. To the OP's concern, it gave me a lot of friends, many of whom are still in my core group of friends now that I am in my 40s. Being on a team also structured my time and helped make me a better student, and gave me a lifelong love of running. Running is still one of the few things that provides joy to me on a regular basis.

Here's the secret, people who have fun are the ones who seem cool. Stop worrying about what other people are doing and what looks cool. Just figure out what activities are fun to you and seek them out. They may be new things, they could be things you have already done. If you're having fun, people will want to be around you as long as you're open and outgoing with these activities. People will seek you out.

if you need some help get some help

professional help

Your worst possible move is to get anywhere near drugs and alcohol if you trend towards isolation and alienation. Getting drunk is a fool's gambit and self medication to bolster socialization leads nowhere. There is a way out of this anomie and numbness, and I really hope you find Him. Choose the narrow path less travelled.