Is it normal to think you sometimes don't exist?

It is normal to sometimes think that you don't exist, but this is a rare occurence for most people. It is more normal to think that you do exist, most of the time. I think that what you might need, is a healthy dose of reality. Perhaps, you might want to discover the wonders of nature. Would it be appropriate to wear pajamas into the wilderness? I think that that would be a very foolish decision.
Pajamas, in some societies, at some times and places are considered to be acceptable in public, at other times or places, or other societies, not. The key is to understand what a society will accept at a given time and place, without causing a controversy towards yourself. In some societies, pajamas worn in public, have recently become a fad. The question is, how daring (revealing) do you want to be?
Of course, perhaps you were just lazy that day? I think that most people become that way occasionally, some more often than others.

if you didn't exist you couldn't think, and you have to exist to think, and you have to think to imagine, and you have to imagine to feel something you're not. mabye this is all a dream but someone who is you is either dreaming this life or living it.

Does exist.* I hate autocorrect. >_< that, and my big fat thumbs...

I think this is normal. I am always wondering if I, and the world at large, try exists, or if it it's all a lie, or a dream, or even some strange computer program perhaps. I also experience déjà-vu on a regular basis, and it freaks me out. I've even had dreams that sort of came true, which disturbed me greatly. Like, this one time I had a dream about a minigame in the MMORPG RuneScape that was EXACTLY like Mobilising Armies. And when they released the actual mini game and I played it for the first time, and remembered my dream... Bricks were shat.

I'm not sure how your story relates to the question, sorry but I do think I exist, but I used to think everyone else didn't. For example, I think it's weird that I'm the only one who can't see my own face.

My ex used to think this too. He was just generally kind of depressed and had mental problems, you might want to talk to a counselor...

They sell rope at Home Depot. I'm just sayin.

I've gotten deja-vu only in the cities.
I often feel like I'm nonexistent or that I'm supposed to exist on some other plane. (if that makes any sense)

I feel that all the time! And it feels really weird like a deja-vu. Sometimes it's even scary, because you just know something happened before and what people are going to say, but everybody just thinks you're a complete retard.

I feel like that constantly, I'm actually used to it now.

normal cause u probly dont, me either :( oh well