My sleeping is off. I sleep during the day and stay up late at night. Is there any medicine that can knock me out at night so I can sleep normaly?

It's a matter of discipline really, aided by some over the counter sleeping aids. There are several out now. One I use is a natural product by Webber Naturals called 'Melatonin'. You don't get a complete eight hours though, I get about four to five hours. Then there is Nytol. Check your pharmacy they are all there; several in fact nowadays that are safe to take.

Tick

There are prescription sleeping pills. They can be addictive, have side effects like disturbed dream patterns or constipation or dry mouth, and for many people they don't work.
There are natural supplements. The most common is melatonin.
There are life changes. Reading or the last few hours instead of TV, earlier dinners and lighter food (eat more at lunch instead), no caffeine past 3 PM, a small cup of not very sweet cocoa or chocolate milk before you go to bed.
Don't toss and turn. Get up if you don't fall asleep pretty soon.
Some people like a radio on very, very low, sort of background noise, of soothing music.
Don't sleep in an overheated room. It's healthier to have fresh air and more blankets.
Exercise during the day. Getting worn out physically is one of the best and most obvious ways to get tired enough to sleep.

After all that, research has shown that some people really are 'night people.'
Many of us change as we age too. I know I have, a lot.

It is a matter of doing it, if you don't go to sleep during the day, you will sleep at night normally. Some of the minor over the counter can help, The natural one named above, is helpful.

But also not everyone gets or needs 8 hours of sleep every night, I seldom get more than 5 or 6 hours a night and have not for 20 years. I feel tired or lazy during the day if I sleep much over 6 hours a night.

Also calm down at bed time, no killer action shows, watch your diet and so on