I can relate to it. I find it very hard to not show emotions, and as you wrote, the negative ones are more difficult to hide, since I'm not always aware of showing. I'm not particularly prone to depression, I only feel a more or less constant anxiety. The funny thing is that even when I try to suppress my feelings about something bad that just happened to me my friend would read it easily and ask what the problem was, and I'd have to talk about it...
Since I dropped some of my efforts to show a good face whenever I'm in the company of others after discovering AS, my co-workers kept me asking questions like what's happened to you, do you feel ok, etc. Nothing has happened, I'm only this way.
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Another non-English speaking - DX'd at age 38
"Aut viam inveniam aut faciam." (Hannibal) - Latin for "I'll either find a way or make one."