I know what you mean about getting depressed after the hypomania starts to fade out. I too get paranoid during hypomanic states. I hear voices and think people are talking about me or that everyone is in on a secret except for me. My psych always increases my dose of Risperdone when the voices and paranoia begin. I would rather be in the hypomanic stage than the depressed stage. I get so very depressed that I cannot get out of bed and function at all.
I plan to call my doctor immediately if I know that I'm manic or hypomanic so I won't get depressed. Especially if I'm having paranoia, I think its important to get that controlled and talk to your doctor about it if thats something you are able to do. Otherwise, I'm not wise on how to stop it myself.