Regulating your sleep cycle is so important to bipolar and it can be hard to manage at first.

You are right 12 hours is too much, the more you sleep, the more you want to sleep and it can trigger depression. Exercise is also important so your body is actually tired out.

Melatonin helped me tremendously as my sleep cycle was reverse for quite a while. I also do make sure I go outside - rain, hail or shine for at least 10 minutes in the morning. It can be helpful to have a bedtime and wake time, and even if you dont sleep, you go to bed and stay in bed for that time and get out of bed on time. Having breakfast in the morning can also help you wake up and prepare for the day. Routine is drummed into us for good reason, it really does help.

Goodluck!