I'm not sure this physical world is real or true either.

I am not sure either. I am pretty convinced that it is one of the most elaborate agreements about how to perceive reality. We see what we see because we are born into it (and conditioned by our parents, teachers, language and its structure, TV, culture, society as a whole, etc.). I know that many people argue, "well, you can't deny the reality of pain when you burn your finger or the reality of physical damage when someone falls from a skyscraper..." But there are examples that prove that even these things are not so certain. Like a woman who lifts a car (!) to get her child from under it, or someone who falls from the 9th floor and get only a couple of bruises... Yes, most people would die, and that's the reality we all KNOW and we don't even try to argue with it or practice to change it... But that one person who fell and got up and walked away? Is he any different? Is he god? Is his body made of a different material?

And as for things like "time" and "space" - it gets so weird and complicated and there are so many things that science can't explain (and if it does explain them, some explanations sound like a bunch of crap that even scientists themselves probably can't take seriously) that one can't help but wonder... is there something fishy about all this stuff we call "real"