Myrosiedog- I agree with everyone here. YOU need to take some time for YOU and she needs to realize is that you have your priorities like your surgery and getting ready for it. You have gone way above and beyond your friendship with her, and now its time for somebody else to step up and help her for awhile.
What you did was the right thing in telling her that shes spreading herself too thin. She needs to go up to her assistant and tell her look you need to start helping me out with the scouts and take over a couple of meetings for me. Now is the time to sit down and have a heart to heart with your friend and tell her how you feel and if she starts with the guilt trip then you just say look I think we need to take a breather for awhile and then you just go. Then after your surgery and recovery then give her a call.