Kendall,
I don't know you very well but I do know that many here feel the same way about you. Take a few deep breaths and figure out what you need to do. If you have to be at the funeral, make that decision and go.
For myself, I wish you would keep your medical appointments and put at least one stressful event behind you. Your friend's family will appreciate your support a week from now possibly even more than today. In a few weeks the real mourning begins and by then others will have moved on.
Feel free to tell me to mind my own business.
SS