Emma - so good to hear that you have some good friends around, at times like these we need them more than ever. I have had an operation a month ago so I have a fair idea of how you must be feeling, although my op was not a major one, or at least I dont consider it to be major.
First of all be good to yourself and give yourself a chance to heal, so eat good healthy, fresh food. and if you must exercise start off by doing something very gentle.
I dont know where you have been cut, but if you find walking comfortable then its a good start, just dont overdo it, it takes a while to really get over the anaesthetic, even if we dont feel sleepy any more, it can take a few weeks to really get rid of the last traces of anaesthetic from our bodies.
So please take it easy, you still can be active by doing gentle exercises.
I hope you are recovering well, big hug for you x