No, I don't think that you are the worst girlfriend ever. However, I think it may be possible that you are not ready for a relationship yet. You could work on yourself first, and then after that, pursue a relationship. I think this is a matter of timing rather than any defect on your part. We all have our own issues to work on, and we could all use growing in some areas. But I think that it's important to set a milestone for yourself, and decide not to enter into a relationship until you reach that milestone.