What can I do in this messed up job situation?

I work for a job agency, they use me as a temporary worker so on my first job that I got thru this agency I got a job at a dog food company by the name of natural balance. Since may i have been working there, not once have i called in to not go to work. I always worked dedicated to this job, sometimes it would be hard cuz they expect so much from with the little experience that one has but i eventually got the job done. Respected my superiors and everything so I had a crucial family emergency yesterday and I had to call in at work, 4 hours go by and i get a call from the job agency and they tell me to not show up to natural balance on monday because they decided to let me go. What I want to know is up what can I do in these situation because i think about and i cant find no reason for them to fire me, i think maybe it was cuz i called in but i had no choice my grandma who lives with me was rushed to the hospital and i had to go and see what was up with her at the hospital. and i just remembered this week at work we had a meeting talking about rules and regulations and one of those regualtions was that it was ok to call in for an emergency cuz we all have familys to take care so why was i fired??? my friends and even workers from there who have heard my situation think its completely messed up cuz they shouldnt have fired me, i hear i can for sure recievce unemployment and some tell me that i should talk to a lawyer about this because not only did they fire me but me and including more than half of the staff at nb dont have forklift certifications and we are made to drive these forklifts so we can load up the trailiers with all the dog food for the orders that companys place and also cuz they are not paying me enough for the things i do at work i know how to drive a forklift, how to use the ups worldship program and have been in charge of doing abf, natural balance delivery orders and will call orders and all i get paid is 8.50 an hour. so what can i do or what should i do cuz regardless what hurted me was gettin fired its not fair please help me