My father was bipolar and it was horrible! I know how you feel, because it is impossible as a child to understand a bipolar parent's behavior. My dad was a lot more manic than he was depressed, and I think it is the manic phases that were the worst. He would blow up at me for no particular reason. He would yell and scream at my mom, throw dishes across the room, to the point where I would be sent to stay at my neighbors house for days at a time. He would never shut up, talked constantly, and slept maybe an hour or two a night, it was horrible.
One time, he quit his job, then proceeded to throw out all of his clothes, buy a whole new wardrobe, a corvette, a new car for my mother, and a van...and couldn't understand why my mother was upset! It's like he thought that we would never run out of money, even though he wasn't working.
He kept coming up with crazy ideas, that just weren't feasible. I can't even name how many different types of businesses he thought he should start, most of them were ludicrous, and he was thankfully talked out of them.
This list goes on and on about his obnoxious behavior during his manic phases. We managed to get him hospitalized once, and on meds, but he eventually checked himself out and threw his medicine in the river.
After a succession of manic episodes, he became severly depressed my senior year in high school, 1996. He wouldn't take his meds, or get help, and the summer after my senior year he committed suicide.
I have had a hard time dealing with all of my feelings about him, over the years. I have been to a lot of therapy, and this has helped me enormously in sorting out all my feelings. One thing that was hard for me was to accept the fact that it was okay for me to be angry with him. I had a lot of anger, but thought I wasn't allowed to be angry because he was sick, it was a disease, and now he was dead, and I felt guilty. But it is okay to be angry for their behavior, esp. in my case where he could've helped himself and didn't. Once I dealt with the anger, I was able to grieve for my lost childhood, and for him.
I really feel for you, as I would not wish this on anyone. Is your father on meds?
I will pray for you and your father! Hang in there, and try not to take your father's behavior personally!

hugs for you!