Can you help me distance myself from a friend?

This is beyond - this person may have some problems. You need to sit down and talk to her and establish clear boundaries. Tell her that you are very busy and that you cannot talk on the phone and hang out with her as much as you once did. Limit phone calls to once a week. Limit visits to twice a month. You have to be direct and tell her exactly what you're willing and able to give her. If you don't want to hurt her feelings, just simply tell her you are very strapped for time, and it's nothing personal. But do not say more than that. Hopefully it will work out for you!