i lost my job....again

i havent lost so many jobs in a period of time in my life be4 now.  i think i did a gd job, but they don't.  im starting to wonder if its me.  am i just not such a great worker as ive thought i am.  if i am why wouldnt they wanna keep me? unfortunately people arent honest with u and not always fair and there are other factors that have nothing to do withn my work....things r so complicated.  i cant really know y i was fired...sucks. 
it is making me question myself and my work.  making me feel less confident.  how do i go look for a job on my merit after someone telling me youre not good enough....and it wasnt specific it was vague and thats the hardest....unsatisfactory work....thats it...thats all is says....i just dont get it...if my works so unsatisfactory why is it difficult for you to pin down what makes it that way?
im afraid i wont have enough money to take care of myself and my family. i think i shd b okay.  there are a lot of programs that will fill in the gap. i hope its enough.