There is much good news (GN) and bad news (BN) in what you write:
It varies from person to person, but once you're on the proper medication:
(GN) your stiffness and tiredness should be much reduced;
(GN) the tremor reduced, but probably not eliminated.
(GN) Your next appointment is in 6 months: your consultant doesn't see your case as urgent.
(BN) Your next appointment is in 6 months: the fact that you ask the question suggests that you may well benefit from some meds now (not in a life or death way, but in a quality of life way). If you can't get an earlier appointment, I suggest you see your GP.