I feel that. I frequently get "I thought you were getting better." No, I felt better than normal the last time we spoke. Sometimes I feel worse than normal. Today is just normal, which means managing some pain. "Oh, I thought you said the treatment was helping." Yes, it is helping reduce the pain sometimes. "Is there another treatment you can try?" No, let's start over.

I'm reminded of a conversation I had with my late best friend. He was incorrigibly optimistic (though fortunately had the grace to not be like this when it came to my disability), and he was a great person to have on side because he was a sheer force of nature when it came to problem solving. Sometimes though, being good at solving stuff meant he wasn't great at being reassuring when what I needed from him was emotional support.

There was a big stressful event at one point, and it was stressing him out too, because it was very high stakes for me and he desperately wanted things to turn out well for me. He would often try to reassure me along the lines of "it's okay, we're going to get through this, the appeal will go fine".

It took me a while to understand why this disheartened me further, but eventually I realised that it was because it felt like we were implicitly saying my future was contingent on this big and scary appeal process, which made me feel even less like my life was in my own hands. I explained to him that if he was aiming to be reassuring, what I really needed from him was to let himself be vulnerable and scared with me, because we actually didn't know whether we'd be victorious against the shitty, bureaucratic system I was fighting; I needed him to be saying stuff like "regardless of what the outcome of this process is, we'll get through it".

It was an interesting realisation because it revealed how actually, his relentless optimism/problem solving was as much a coping strategy for himself as it was a way of supporting his friends. He felt overwhelmed when faced with a potentially unsolvable problem, but ofc, so did I (and if he wanted to reassure me, we needed to be on the same page in that respect).

This is only somewhat analogous to what you describe, but I think there's a similarity in how people aim to reassure because they feel uncomfortable with the truth of "this is bad and it's going to get worse and that's fundamentally a cosmically unjust situation". I think your actions were justified and reasonable, because you've already had to come to terms with the injustice of ill health, and it's not reasonable for you to have to do emotional labour on other people's behalf because they're fortunate enough to have not gained that understanding.

In the thing with my friend, I was able to explain what I needed from him in part because we were so close. However, refraining from talking about certain topics (such as health) is also a valid way of approaching this problem. If people want to be able to support you, ultimately, they need to meet you where you're at. If they can't do that, then fair enough, but they can at least stop making you feel worse.

Sympathy and solidarity, friend