Should I leave my job even if I havent found another one yet?

I am 20 and have been working at a Papa Murphy's since I turned 17. (Its a take and bake pizza chain located in smaller cities). Two of my favorite managers have left in the 3 and a half years since I started. I am much less motivated to go into to work everyday. I am tired of smelling like food after work, and putting up with gluttonous customers who are in disbelief whenever I say "yes, that is extra cheese". The store owners are nice I make $8.50, but my heart is not in it any more, and its making me more resentful every time I go in. I am not a mean person, I am nice to all my co-workers and customers. The only serious issues I have are my manager she also gets on me for "not going fast enough" pizzas are pretty easy but, I have cerebral palsy which effects my ankle on my right foot, and my wrist on my left hand. So making pizzas wears them out considerably. She also gets on my because when she or the owners are not around I will gladly give a customer an extra topping without charging a $1.50. Obviously she only notices this when I foolish do it when she is around. Other than that I work hard, I even stay extra hours just to help if they need me. Unfortunately two of co-workers left last month, and a third just no decided to quit. So they may not like me leaving. I will put in a two weeks notice, I wont just take off. But I can promise them I WILL NEVER GO BACK THERE NO MATTER WHAT. I am just done with it, there is nothing that can make me stay, and I would be much happier to not have to go in their. I loved it for awhile but it is time for along overdue change. P.S. I can deal with being unemployed for a month or two.