My insomnia is threatening my job and my health

For the past 3 nights, I have barely been able to sleep, even though I go to bed at 8 PM. It's like I fall asleep for a couple hours, and suddenly I'm jerked awake and my body pumps itself full of adrenaline, keeping me from falling asleep again. It's already affecting my performance at work and I've been trying to prevent seizures, but sleep deprivation is a major trigger for them. I've tried nearly everything: aromatherapy, meditation, counting sheep...why the fuck can't I sleep? I feel like I'm going to collapse as I type this. This is fucking up my life and it has to stop before I get fired or develop epilepsy. Why can't my body stop pumping full of adrenaline all night?