I was told that the anti-depressant they put my Mum on would take about a month before she felt more positive.
I suppose as with all drugs some don't suit people, especially with whatever other drugs they are taking. (My Mum was on madopar and citalopram)
Anxiety can be part of PD, and so I guess if you already having an issue with anxiety then coping with it may be harder?
"that's just the way it is - deal with it!" not very supportive....you could ask how they suggest you deal with it?
Supporting someone with anxiety is hard (been there - done that - got the T-shirt!!) Watching and feeling helpless is not easy. The PUK helpline nurse will hopefully have some more positive suggestions than "deal with it!"
Look after yourself