Can you say "If you are happy, I, too, am" ?
You can say that, but it's a little awkward. The issue isn't the meaning, which is correct, it's just not the most natural way to say it in English (at least in my variety).
if you're happy clap your hands lol
Se vi sentas nun kontenton, plaŭdu tuj :D
"If you are happy, I am as well." I got that wrong :S