Firsly don't worry about it. Panic will keep you in the cycle.
If you cannot sleep stick to the 'desired pattern' Get up when the alarm goes of but avoid sleeping then. When you have trouble falling asleep be okay with it. Just as long as you're letting your body rest you're doing all that is necessary.
Make sure you don't have caffine drinks at least 4 hours before you intend to go to bed. Be sure to check many drinks now have caffine added.
Soothing music... slow kind or a nature sound Cd helps many people if you haven't already tried that give it a go. The music should be wordless so that you mind wind down on thinking.
You could also try an evening meal that includes turkey, that has a substance that causes people to feel more sleepy. Then in the evening when you feel tired go to bed earlier.
If you're tired during the day avoid napping longer than 45 minutes. A good way to get around the shortened sleep cycle is to meditate for 30 minutes instead of napping.
It's been recorded that 20 minutes of theta brain entrainment will bring you back to alertness.
In all take it as something that will soon pass and not worry too much about it. If you don't panic about it then it will resolve itself.
The problem could simply be a change in diet that you haven't notice. The stress you might be experiencing in your studies might be a factor and if it is do some stress relieving exercises and meditation.
Alex