Feeling lonely even though I have 3 kids at home

This might sound weird but I feel really isolated. I love my kids but I don't have friends anymore. All my college buddies moved away or we just grew apart. I spend my days with 5-7 year olds and my wife is always exhausted. Don't get me wrong, I'm grateful for my family, but I feel like a shell sometimes. Anyone know how to make friends as an adult when your main identity is being a dad?