system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why am I often very tired during the day, but struggle to fall asleep at night?
gpt
What is your activity level?

 How much caffeine do you ingest and at what time? 

What is your diet like? 

How much stress is in your life, and how much of it is long term worries out of your immediate control (like large debt) and how much is short term stress (such as tasks at work?)