Break down the problem, and identify your goals in dealing with it/them. Is your problem one or more of: 1) fear is unpleasant and you'd rather not experience it, regardless of any other experienced or behavioral differences? 2) there are consequences to not using an account? 3) there are consequences to trying to use an account when it's not necessary?

You might address the fear via therapy, medication, meditation, and/or introspection - though not in that order, please. Introspection should include trying to separate out the components of the fear, in order to decide how much to focus on your perception, and how much to focus on the second thing, behavior.

You might address the actual problems of too many accounts by having fewer - just don't sign up for things that aren't going to be a net positive value. Or consolidating into a PasswordSafe or other place to list the accounts, so you can see when you've last used something. Or simply a checklist of daily and weekly information to look at.