I cannot sleep until 5 AM?

I'm usually a late sleeper (around 11 PM) but after summer started I began sleeping late and later.It has only been a few weeks before this started. Now I can't get to sleep until 5 AM. It's always the when the sun comes up. I can usually wake up at noon. Again this has only been the last couple of weeks. I really need help! I am not depressed and after a few hours of sleep I function properly. I doubt it's an actual sleep problem because It is so recent. I have a week before I need my sleep cycle restarted.