I know the financial state. Been there quite a few times myself. However, what you describe could be very serious.
Won't eat: something may be wrong
Wobbly or unsteady on feet: something is wrong
Can't control bladder: something is VERY wrong
Blood in urine: something is VERY WRONG
All these together: CALL ANOTHER VET
From just what you describe it sounds like your cat may have soft tissue injuries which can range from bruising all the way to ruptures. Without knowing what the true problem is, forcing food could be harmful. If any of the internal organs or the intestinal tract or urinary system have any ulcerations, lacerations, or ruptures, the food could cause serious damage or even death.
Sorry, I'm really not trying to scare you, but WHAT YOU DESCRIBE *could* be very serious.
I've had a lot of success calling vets and explaining my financial situation and the animal's condition. If you have a ASPCA vet or a local Humane Society vet - call them. One of the best vet's I've ever dealt with was a Humane Society vet and she charged me almost nothing when I was unemployed and one of my cats took very ill. I'm talking $5.00 (just five) for a complete visit, x-rays, and bloodwork. Other vet's have gone against their stated "payment in full at time of services rendered" policy and allowed me to make minimum payments monthly.
A second opinion may actually reinforce what the original vet says and the only issue may be bruising and your cat simply needs time to heal. Meanwhile, a vet is your best resource for anwering your questions. At least your mind will be eased if the second vet completely agrees with the first one.