Man.. that's bloody awesome to hear Xue. That must have really felt good, and lit something up in you, well done, it's well deserved after all the immense trials you've gone through...
Yeah it definitely is the case for any injury or rehab of 4 steps forward, 3 steps back... my knee has been doing great but is currently in a bit of a downer, quite a bit achy at moment, but my knee rehab program has helped immensely over the past 2 months or so.
I've been trying to really focus on my mindset, and not see a painful phase as a sense of regression, and not attaching any 'forever' or catastrophic thinking to it ("ahh it must be getting worse, it'll never get better" etc). Just being more curious when it comes up, "ah, there ya go there's that again", and adjusting accordingly, not training that leg too excessively, but keeping it active still.
Glad things are looking up. Take it slow, and as hard as it is to accept, remember you're not 25 anymore.
It used to really get me down that I couldn't do a lot of things as well as I could, but these days I try to be more thankful that I'm still in there swinging.
And in some ways I see it as a blessing because it frees me up from all the things I was trying to maintain and now I have the liberty to enjoy what I'm still able to do.