That makes sense about Cymbalta making you manic when you were on it. One of its common side effects (or adverse depends on the website you go to) is "insomnia." So it probably induces mania in some people who take it.

The delayed phase sleep syndrome means that you fall asleep after normal hours -- past midnight or not until the morning. The two main treatments for it are light therapy (think: SAD "seasonal affective disorder" light that you sit in front of 20 minutes a day) or chronotherapy (the time you go to bed each night -- you intentionally make it later than normal and do that every night until your circadian rhythm kicks in again).