I'm glad that you're going to get some help from the social worker. Since she has helped you in the past, that should alleviate some worry there.
If taking more money out will make you feel more secure, then you should do it. You have so many worries already

Even though you'll be awake for the procedure, you may be sleepy, so the time will probably go by fast. I have a feeling you will sleep for a lot of the time following the surgery