potentially being replaced?

The team will grow with time. Newer people will join with enthusiasm. They might criticize your work without knowing the full picture, and can't wait to take it over and do it in their way. You might start to think, is there anything wrong with me? why does it happen?

Keep in mind that YOU DID EVERYTHING PERFECTLY. THERE IS NOTHING WRONG WITH YOU.

You must feel very hard and hurt about this. I've been there, and maybe still am in the zone. Frankly, I don't have good suggestions for this. All I am trying to do is to STICK TO YOUR BASIC PRINCIPLES (take good care of physical health and the ultimate goal is to improve our tastes), try to cheer up, and wait for the proper time.

It doesn't imply that you are unqualified, but because of other factors, for example, you didn't present your contributions well or now they have much better resources than those when you did for your work. Try to learn from it and move on. You've got tons of other work and your own life ahead to live.