Open Question: I have a job but it's temporary. What should I do in case I lose it or just want to change?

So I managed to land a job in this economy. After eight months of searching, I ended up working for the post office. The only thing is that my job is very temporary and all Casuals are constantly on the verge of being fired. Also since I work from midnight to 7:30 without a car, the commute is rather grating and I have hardly any free time. I can't hang out with anyone on my nights off. Lately, everyone and my mom has been busting my balls about how I'm gonna get fired any second now which makes me concerned about the future. What jobs should I apply for after the post office? Is there any chance of me working in a mailroom or getting paid anywhere near $10 for a job during the day? I don't have a college degree and the only real skill i have outside of the post office is developing film but I think that's dying out. I'm willing to work retail to keep my apartment but I'd rather not (if so, I'd like to work in the backroom somewhere). Any advice on anything I've rambled on would be great.