How Can I Grow My Hair Quickly After Getting It Cut Way too Short?

Red is where my hair used to go to. I'm sorry I don't have a better before photo

I just got back from the hairdresser and he cut off way too much hair. I asked for 5-6 inches off and he cut closer to 8. My hair is so short now and I absolutely hate it. I bawled my eyes out on the way home and I genuinely feel sick to my stomach when I see my reflection in the mirror. How can I quickly get my old length back? I bleached and dyed my hair in the past, but the hairdresser cut off all the bleached parts, so it might as well be virgin now.