You are definitely more than just a job title. Focus on the aspects of who you are that you like the most and seek to fulfill them on a daily basis. You'll feel better about yourself and your situation, and maybe you'll even develop a healthier perspective about your identity than you had when you were working full time.
When all else fails, dance it out. Or sing it out, craft it out or run it out. Just do something healthy and constructive to boost your mood when you're down. Letting out bad energy opens up space for good vibes to come in. And who doesn't want to dance around to the boy bands of yesteryear every so often, anyway?