Muse on work

So...after writing such a positive post on Quick Chek. I was fired from there on Friday, September 18, 2009. I decieded to write a letter to the manager that fired me. I feel I was wrongly fired. She said the reason I was fired was because I wasn't fast enough. What confuses me the most is everytime I worked I was praised from my work and how well I was doing. They would say that I was doing much better than several other people when they first started. I never recieved a warning that I need to improve my performance in anyway otherwise I was risking my job. It simply went from "You are doing great!" to "You are fired!". I was in total shock on friday. She also mentioned that they try to fire people within 30 days otherwise it goes on her record that she fired someone after 30 days without 3 write ups. She said that they know within 2 weeks if someone is going to work out. I technically was only there for about 10-12 days INCLUDING the days of training. Technically she didn't even give me two weeks. Even though I was in the system for the past 30 days I only worked AT MOST 2 weeks out of it. I also should have been at least been given a warning or something that I needed to improve. I had no idea that I needed to improve so when she asked me to come in for a meeting I wasn't expecting to be fired. I thought it was just a review after a month and maybe she would mention areas I needed to improve on and that is it. Anyways, I am working on looking for another job. I hope I get one soon! I REALLY need money!