Take their criticism of you and learn from it. I know it’s hard, but the best you can do is trust their actions. Meaning that healer is probably really good and knows what they’re doing. If you followed them you would probably learn how to be faster, knowing they would be able to keep you alive. Perhaps you would of learned something else. It’s like being under the spot light and the pressure is on. Like a test.

I know people will usually defend the tank in this scenario, but taking advice like what you described and following through is good experience as a new tank. Just go with it. It’s only one dungeon run. That was the chance to push yourself.

Keep it up though and don’t be afraid of criticism. You will grow.