I'm sorry you're struggling to enjoy humor in your life. I think for many, like me, it was/is mood related. I no longer struggle with a flat feeling. I have periods when I laugh, smile, and make jokes much of the day. Many periods.

When years pass, it's difficult for me to remember exactly how I was on certain medications. Others I remember better. I know that when I was finally weaned off Lithium, I felt like a cloud lifted. That was maybe 6 years ago? A lot of water under the bridge since then.