How do i prepare myself if i think im going to get fired?

I'm having a lot of problems at work and I think i may get canned soon. I have been searching for other positions and I haven't had any luck. I have been trying employment agencies and applying on craigslist and so on. If I cant collect unemployment, what else can I do. also, what are the signs of getting fired. My bosses are giving me silly tasks to do. For example, I am the senior partner (law firm) secretary. He told me it is my responsibility to make sure everyone does their work correctly and also make sure there are no typos. I get all work and distribute it to all workers, including attorneys in the office. Its a fairly small office. I have a ton of work myself. This i find very silly. Also, the other workers are cold towards me. I am killing myself for these people and trying my best. What are signs of getting fired and what can i do to prepare myself besides looking for another job. If i do get fired, what are some ideas you all may have. I have a lot of bills to pay and an expensive rent. please give some advice.