Make new friends. Great friendships are not base on how long or how well you've known a person, but how well you connect with another. That can bloom amongst new friendship with a little bit of time as well.

I speak from experience. I was in a similar boat. All my closest friends growing up were the wrong fit for doing anything entrepreneurial much less a startup. A friend I met through another mutual friend but rarely talked to turned out to be one of my closest friend and became my previous cofounder. It worked out great.