“No man is an island.”
Put more effort into reaching out. Join a club. It feels like it but you’re not alone man(or woman).
You can pursue running without sacrificing social interaction if that’s what you want. There are others like you out there who aren’t even runners. You say you can’t find any but id wager you haven’t looked hard enough. You can have a social life with people who don’t share the same lifestyle as well. Just need to be a bit more open minded about it.
As an introvert I know how freaking hard it can be to get out of your shell and break the cycle. The first step is trying to get to know people who at face value don’t seem like someone you’re interested in. Accept invitations even if you’re not initially excited - or invite others to do things even if they tell you they’re busy. You might surprise yourself