There is, of course, a test to see what happens to your 'self' if your brain is basically turned off or rebooted, so consciousness, if immaterial, would logically go on if it is continuous and not dependent on the physical brain. This is best initiated from an awake and conscious state so as not to confuse it with normal sleeping.
Whack yourself, hard, on the head with a sledge hammer. I would say ball peen, but that is likely to actually do more harm if you use the wrong side. (But I was tempted, ohh, so tempted. Thread fatigue, mind you.) Get a friend to help you if you need to.
If my rustic manners offend, you could also try to convince someone in the medical field to put you under, preferably an induced coma. Again, due diligence begrudgingly obliges me to add to not forget to give them a wake-by date.
When you get back, you will have a very good idea of the fact that when you are out, you are not around. The brain hosts the mind, and that is exactly why in both scenarios you can be rebooted. End, and very end, of story.