Hi bluedonna, firstly kudos to you on how active you are helping others and with that creative drive. And I know you get something from helping others/using that drive but it's got to make a real difference to them too!!! So good on you!!!
........the trouble sleeping, well IMO it's understandable.........depression can mess with your sleeping patterns and for some people interrupt them...........and the high's, well if you've still got that "buzz"/that build up of energy it's got to be harder to hold onto sleeping patterns.
For the possible bipolar symptoms.......it would probably be worth getting that professionally assessed for some firmer answers but for now............
The better times could come from a combination of things do you think??? Feelings of achievement, validation, release, self-expression, excitement...........???
Do you think you could create more opportunities in your day-to-day life in touching some of those things a little more often??? Try to channel some of those needs on a smaller scale but more regularly??? Maybe.......and just ideas.........different art forms.........energetic activities.........different kinds of voluntary work???
But if there are any issues in your self worth/lacking the feeling of being in control of your life coming to the surface then maybe worth pinpointing some of the reasons for those, working through them and finding some things to help you with moving on from them a bit???
Anyway.........just some thoughts..........
And again...........kudos to you on your clear talents, and desire to help out others!!!

Alison