You wrote:
“I come across as bitter?”
Yes.
“How can that be, when I’m laughing so much?”
Think of Job 17:2 in the Bible in Basic English translation: “Truly, those who make sport of me are round about me, and my eyes become dark because of their bitter laughing.”
BITTER LAUGHING.
If the shoe fits...
Shoes don't fit. I have to ask in return whether that quotation means that your eyes have "become dark"?