We Jews are celebrating the Torah (Law) Feast. We are commanded to be happy and thank God for giving us the Torah. The Jewish Magazine lists 12 reasons to be happy even if you are depressed, and the last paragraph is worth quoting:
Reason 10. We can breathe.
Reason 11. We can smile.
Reason 12. We can dance.
If after reading the above list, you still do not feel happy, then I suggest you buy a bottle of Russian vodka, open it up on Simchat Torah, drink half the bottle, and go to the synagogue. You may not achieve true joy, but you will be too drunk to be depressed and all the children in the synagogue will enjoy watching you make a fool of yourself.