From what I've read here and from my own experience, you aren't doing too bad at all! I was only at 95 flex at 8 weeks (according to the doctor, who just eyeballed it rather than measure). And my extension wasn't quite at 0 yet (and still isn't). Every week it gets a little better. Eventually you will be at full ROM and won't even remember all this recovery. I think every person heals at their own pace, and even for every person each knee is different.
But I do understand feeling down. I was at my lowest point probably weeks 5-8, emotionally anyway. I have never had such a big procedure with such a long recovery (remember, it takes a full year), so when I hit about 4 to 5 weeks my brain was saying "Enough already, I'm over this!" but my knee was saying "Not even close" and that disconnect was disheartening to say the least. You will get through it.
As for all the different sensations and new pains, etc., I totally get it! I am the same way. I have found myself more than once humming the old 80s INXS song "New Sensation" because that's what every single day brings. It's frustrating on one hand, but it's also fascinating because we are feeling our body heal.
The step at PT was hard for me at first too. I am in week 10 now and I think I only mastered it a couple weeks ago. And I had hip pain too, and the physical therapists taught me a couple nice hip stretches that helped. Talk to yours, maybe they can recommend something.
Take care, you've got this!!