Hello, fellow nurse! And welcome to BoneSmart. Well, yes, that all sounds familiar so don't fret. These knees take a looong time to settle down and get normal.
As for returning to work - are you having a staged return? Do you work full time or part time? If so, how many hours, what kind of shifts?
As I have worked it out, you're planning to return at around 11-12 weeks. Hmm - that might be doable but personally, I'd keep a caveat in the arrangement that enables you to take another couple of weeks if needs be and that allows you to go back on sick leave for a couple more weeks if you find it too much. (I know how hectic delivery rooms can be!)