It is understandable that you did that, even if I do think that you're not dealing with the real issue and are punishing someone for success based on your own feelings of inadequacy.

I disagree that her success or your jealousy would be more damaging your mental health than you accepting something that you should be dealing with instead of hiding from - that is, the sources of your jealousy.

I hope that you're doing something like talking to a T about what causes you to have such strong feelings of jealousy toward someone that would warrant you to abandon someone that you clearly considered a friend. If you are that's good and I have a suggestion.

If you are working with a therapist on these issues, if your friend means anything to you, explain to her your feelings and that it's not about her personally but that you're dealing with some issues that are related to her recent success. If you word it that way and explain that this is why for now you have to unfriend her on fb, maybe the relationship won't become a burnt bridge.