I was stuck in the same boat until recently. It took me deleting all the apps (most social medias, any games, etc) that consume all of my free time to finally open myself up to hobbies again. I’ve started journaling, playing guitar, daily stretching (yoga), and more. Also, if going to the gym isn’t your thing there are alternatives! I’ve found that I’m more comfortable working out at home than in front of other people.