When you sleep your body heals itself so when you lose even a bit of sleep your body loses some of its oppurtunity to heal itself. One of the areas that sufferes the most is the eyes.
The eyes heal themselves throughout different parts of sleep but they have to do a lot of work during sleep as well. So if you fail to get enough sleep their is a chance that you will notice an increase in eye floaters.
Another reason that you see more floaters when you get less sleep is the fact that your vision is often blurry when you wake up from a night where you did not get enough sleep.
If you are upset about your eye floaters and know that you do not see as many of them when you sleep properly you need to make sure that you get enough sleep every night.