How long will it take for Invisalign to close the gaps the dentist drilled in order for my teeth to move?

Yesterday I put invisalign for the first time. The doctor drilled 8 on top and another 8 on the bottom to have space for my teeth to move over the course of the treatment. But I am totally freaked out due to those big gaps between the front teeth he drillied. I wonder how long will it take for the gaps to close.....or will they ever close?? How soon will I see the result? They do not look nice at all. I started to miss my old teeth although they were overcrowded.