OCD about exercise and fitness to cause insomnia?

I'd be so happy if I could point my OCD at my workout regimen, or lack there of. I worked in the mental healthcare field for more than 10 years and do suffer from OCD. Insomnia is probably more a symptom of your OCD than your exercise. Recent studies show that time of day doesn't have as big an impact on us as previously thought. Though other studies suggest that working out 2 hours after eating does have a rather significant impact. Though more research needs to be done.
Most likely the anxiety and thoughts of exercise are the reason you can't sleep. For me, it's organization. Once when my closet rod broke and all my clothes came crashing down I couldn't sleep because even though I couldn't see the disorder in my closet I knew it was there. It kept me awake all night. I can't sleep if my sheets don't match. That kind of thing.
If your OCD gives you the feeling that you didn't do enough or didn't do the right kind of workout this could contribute to your sleeplessness. If you workout right before bed you may still be thinking about it and your mind will have trouble shutting down. If it becomes bothersome there are lots of meditation and deep breathing exercises you can do. Or you can try PM yoga or PM Tai Chi. Both of which are specifically designed to relax your mind and body. That they're a form of exercise could also help satisfy your OCD if meditation and deep breathing alone don't.
Beyond that, medication and/or therapy can work wonders. Good luck!