Ah....Things are getting tougher & tougher these days, unfortunatly, as you say, generally as a contractor, the pay isn't so good, well, it's great for the company doing the contracting, but not so for the workers..... and even worse when it's not full time....
Have you considered renting a room out (if you can) which would go some way to paying the bills?
Hope you find something else....as you say, when you don't even know when you'd work, if he can keep you on, it's not so easy doing anything else... what about a bit of couriering?? I did that for a while, it meant they called, I said yes or no, depending upon my availability.... just a thought.