How to sleep immediately?

I've been on fluoxetine 3 weeks and in those 3 weeks I've had next to no sleep. I can't take it any more. I'm so tired but I just can not sleep. I've tried warm baths and hot drinks and relaxing music and sleeping pills and nothing is working. I've been in bed for 5 and a half hours without sleep and I have school in 4 hours. I NEED sleep! What do I do?