Don't worry, you're not the only one that does this. Plenty of people do this to avoid having people worry for them. If you do want to tell the truth, why don't you tell a close friend or family member? If they're a good friend, they'll listen to you and help you cope. Your family cares about you and should stand by you, too.
If you're not ready, try writing about all your feelings in a diary or a letter that doesn"t go anywhere...
I genuinely hope you're doing fine, though. You'll get out of this rut in time. (: