I feel like I've burned out..

<p>Greetings. Over the past few weeks I've been at an all time low during the nighttime. My junior year, (last year) I was able to do work efficiently at night and go to sleep at around 1-2 AM. I had great success my junior year due to my nighttime work schedule. Now, I'm at my senior year and I have trouble staying awake past 11 and it really affects my school work. I'm captain of the swimming team and swim Mon-Fri 5PM-6:30PM and when I have practice with my school which is Mon, Wed and Thu, I'm at the pool 3:30-6:30. This has never affected my schoolwork so I am clueless to why I am having trouble staying past 11. I have started working Saturdays and Sunday's 8 AM-4PM but it is not stressful work. Could this be a factor? Any tips to stay up? Thank you in advance, I have gained so much inspiration and success thanks to this forum.</p>