If you're always terrified of being alone, you may have autophobia. People with this condition have an irrational fear of being all by themselves.
If you love solitude, savoring the opportunity to have a little quiet time by yourself, you definitely don't have autophobia. While everyone feels lonely or isolated from time to time, autophobia causes devastating anxiety for people who suffer from it. Sometimes they specifically fear handling things on their own, being abandoned by loved ones, or simply spending time without other people around. The Greek roots of autophobia mean "by oneself" and "fear."