Hi Renee,
Welcome to the moyamoya family. I'm sorry to hear that you suffer with this disease and other problems as well. It sounds as though you're frightened and need some answers, bless your heart. Well, I may not have the answers, but we're all here for you if you need us in any way we can.
There are a couple different types of surgery for mm, which type are you having on June 1st? If you read the posts here, or many here who has had surgery will tell you that the surgery isn't painful. The headaches you're having are probably much worse, which is a symptom of mm and hopefully after the surgery you'll be a new person again and get the proper blood flow to the brain.
Some people are up and moving around the same day. In my opinion Renee, the surgery is crucial for mm, it will be well worth it, rather than taking a chance of a possible stroke. The risks well out weigh the consequences. I urge you to read the many posts here where people have had the surgery, it may be comforting to know how well these people have done. This website is full of information to help you Renee, read all you can and ask all the questions you need to.
We have you in our thoughts and prayers.
God bless,
Mar