Humans are social creatures; you need to have friends to feel healthy.
"Friends" doesn't have to mean "Close friends" – you can hang out with coworkers, your neighbors, join a club for one of your hobbies and talk 'shop' with them, all of which are important to emotional health as well as helping you be a more rounded individual.
Because your faith is perhaps different, or even in conflict with the faith of these friends, you will have to keep a line between "friends I have coffee with after work some days" and "a veritable brother I can turn to when everything falls apart" – For that, you really should find someone whose faith is like yours.
But even in a church, people are all different and you can't just assume you'll be good friends with someone because you worship the same God. Be normal friends with them first – hang out some times because you know each other from church, and hopefully you can form a few strong bonds some day.
But even having 'light weight' friends from church can help combat the emotional drain of feeling isolated.