Is it normal that i believe that this existance is just an illusion?
I believe that our reality is nothing but a very convincing illusion (Matrix, anyone?). I believe that one's reality are the things you percieve on your own on a subconcious level. I read somewhere that humans are not physical beings: rather, we're beings of energy living physical lives. Since energy can be anywhere and become anything, it only makes sense that reality is a moldable format that we mold to our liking.
We may be 'stuck' in this 'reality', but we can bend the definition of what we deem real and change our reality (therefore making this one a mere illusion). Dreams play a large part in this. When we're unconcious, it's easier to redesign and create the world around us as well as the very universe.
In short, what may have been fiction before can become very real in the flash of a night or a series of dreams. These things don't even have to be real on this plain. In the Multiverse Theory, anything and anyone can and will be real in different plains. Plains in which we can reach in our dreams. When we die, those plains will become much easier to access.
Nothing is impossible. Anything can become a reality. It all depends on what we desire as individuals.