If I may make a suggestion? I ran into this a lot when I was deep into doing my own thing.

"Thank you for the kind words. I appreciate it." It got me through years of those conversations.

If you want to take a step further in conversation, I'd also regularly use it as a springboard to encourage people to go make a difference somehow. A person who feels inspired is primed to take an action, encouraging people to go do some volunteer work, donate to a charity that resonates with them, or whatever works decently.

I can't speak for your experience or how you'll feel, but the awkwardness went away for me when I just started looking at it as an opening to help more people instead of a lack of their awareness of how brutally ugly surviving Bipolar Disorder has been for me.