I think I may have insomnia but I'm not sure. Help?

Okay here's what happends EVERY night:

- It takes me at least an hour to fall asleep.
- I wake up at times like 1 AM 2 AM 3 AM 4 AM and 5 AM every single morning.
- When I wake up I feel like I haven't slept at all and want to go back to sleep.
- In school and during the day I always almost fall asleep, the only thing that keeps me awake is the fact I'll most likely get a detention if I do.

So do you think I have it? Or it's just a result of stress? Please help.