I really feel that spurts of happiness followed by challenges and hard days are all a part of the process. I think you are portraying Sunny very well, and all of her friends are very much in character, too.
Once you get some distance from this, you will probably be surprised by some of the subtle details and powerful messages you have entwined in this story.
It's like you're passing through a fugue state - what will come out the other end will have more to do with your experiences and your own voice, and your muse than your plans :)