Depends on your area and how close you are to a hospital for instance where most of the staff work round the clock shifts. Many families manage to work out a routine between mom's job and dad's job such that they only need care on the overlap days. If you live in an area with a lot of single parents you would have better luck although those families often need subsidy which you would have to join an agency to be able to access. Go to www.kijiji.ca and find your city. Under services select childcare and also under jobs select childcare and put evening into the search box to see how many ads it brings up of people needing evening care. For sure decide if you will do daytime or nighttime care as you will need your rest for one or the other timeframes but since you don't have kids to have to worry about it does mean you can work the hours needed and sleep whenever available.

If you share where you are located there may be someone else in your city that would have some specific information.