I know, as you do and probably everyone on the forum that exercise is important and yes, if you find something you enjoy and make it a habit part of your routine then brilliant. Unfortunately Parkinson’s doesn’t suddenly turn on an exercise button, we’re no different to most of the general population who know they should be more active but don’t actually do anything about it. The worst thing you can do in my opinion is get hung up about it, feeling guilty because you haven’t done the recommended time or whatever does nothing but make you feel bad and that achieves precisely nothing.
So long as you move you will be doing something, have a stretch and you will be doing something and when this period of not being motivated for whatever reason passes you will pick it up again, maybe try something new. There are loads of videos on you tube maybe have a look at some of those.
Sometimes life gets in the way. For lots of reasons I won’t bore you with, 2019 and 2020 were not my best years and I don’t wish to sound dramatic here, but surviving was my main aim everything else had to wait. It has taken most of this year to feel properly well and my exercise routines have only recently got going. That’s the reality, that’s what you live with and you do the best you can with whatever it throws at you.
You said you were in denial and wallowing in self pity. That is a big thing to admit. It is also exhausting and confidence sapping. In your efforts to find your new normal you have identified exercise which is good but you are worrying if you are doing enough, the right type etc etc which if you are not careful will make it a chore something you have to do rather than want to do. So try to relax a bit, enjoy what you do do and go from there.
Just a word on the personal trainer. Maybe it wasn’t the right one. I had one and although he was good and I enjoyed it it was hard work. Walking to and from his studio plus an hour session was exhausting took the best part of 2 hours and felt like it disrupted the whole day. Now I have a trainer come to me at 9 twice a week for 30 mins each time. One session is on core strength the other stretching. She brings all the equipment with her. It has made all the difference and I am doing more myself on other days as a result. By 9.30/45 am it’s done and the day is mine…
Good luck in finding your new normal and enjoy the process other things will eventually fall into place. If every now and again you have a hiccup or two and it all falls apart, just pick it up again when you can and move on. I wish you well.