If you are really tired, try a few things:

1. get an upright bike, you can find an old 3speed on craig's list for cheap. These are more fun to ride, I feel like Mary Poppins, or that pig in the Geico commercial yelling "weeee! weeee!"

2. ride slower, enjoy yourself. you'll be awake because your body knows it has to be alert. but trying to have fun will help.

every time I feel like not riding and don't I regret it. Every time I decide to ride anyway it makes me feel a lot better when I get to work. Just keep trying.

As far as insomnia, I often read to fall asleep, it takes my mind off things (if racing thoughts are a problem). I make sure to read fun light stuff at night, nothing that will get me excited or thinking. Yoga is starting to help, just the focusing on ignoring everything but your breath helps me calm down.