If there was something smaller than what is called the quantum level and therefore imposssible for man to see would that stuff be classified as nothing even though it might be the building blocks of matter and the building blocks of everything?
It's not a question of Quantum simply being the smallest we can see. The models based on that experimentally derived notion are ASTONISHINGLY accurate, like to twelve decimal places!
Scientists don't just make this shit up, you know. They have pretty solid reasons for thinking that things really are quantised at the subatomic level. I'm not going to even attempt to explain it all, it's way beyond my level of understanding and, it seems, way beyond yours. I suggest that if you're genuinely interested in all this stuff, you actually sit down and take the time, and study, to actually learn about how subatomic physics in general, and quantum mechanics specifically, works - because until you do you're just mouthing off.