It's being a while since I haven't written anything new on the fascinating subject of self-consciousness.
Here I have compiled a small procedure to verify that you are yourself and that you are alive.
- acknowledge the fact that you somehow can remember the following three things
1) this procedure,
2) the name of that person you find so hard to remember (in my case "Marilena"),
3) that word you always find so difficult to memorize (e.g. "gosub")
... this already reduces the chances that you are somebody else. Then,
- open your eyes slowly
- gently clear your voice
- ask "what time is it?" in the first language which pops in your mind
- verify that you recognize the language you just used
- verify that you understand the answer (if any) that you get back
Unfortunately, while not passing any step of this procedure guarantees that you are actually not "you", passing each test of this procedure does not fully prove that you are you, but it does lift many of the doubts unless you are a mathematician, or a computer simulation, or a philosopher, or a schizophrenic, or a hypochondriac, or a fictional character.
About being alive:
I am still figuring out how you could demonstrate that you are alive but so far I haven't come up with a reasonably convincing proof other than jumping out of bed when you hear the words "bring the garbage out!".