1 sheep, 2 sheep, 3 sheep....

It seems I've become an insomniac. I haven't slept properly since last Tuesday. I'm currently surviving on 1-3 hours a night. 3 is good. Very good. It's making me feel horrific, I'm having horrible dreams, it's not doing me any favours healthwise (I have apparently some strange viral infection that is playing games with my heart rate and making me feel generally rather bizarre.). I want to go running, in the hope that it'll burn me out, but I can't risk it with my lungs being as rubbish as they are. All I want is sleep and I just can't get it. Any ideas for things to help? Sleeping tablets aren't working (prescribed ones. I have two types and neither seem to be doing anything.) neither are hot baths, lavender oil, milky drinks. Suggestions needed!! I need some sleep! I have an exam on Monday and my stress levels are even higher cos I'm not sleeping.