Why am i tired all day?

I dont seem to have energy the whole day. I wake up at 6:10 will showee and be so tired i go back to sleep another 30 minutes. Then i go to school all all day from like 8 to 3 go to the gym for an hour work fom 4:30 to 8 get home at like 8:30 eat dinner and go to sleep at 10. On some days i only have one class so i study most of the day. Like today i dame home early to sleep because i was so tired. I dont know why? Any ideas?