Frankly I don't think you've received much accurate advice above.
I can't imagine insurance would cover cancellation due to a new job. At least I haven't ever used a policy that does.
On rare occassions I've heard of a cruise line bending a rule to refund penalties to reschedule due to a death in the family, but honestly even that is rare.
You can certainly try and plead your case to Customer Service, but in my view it's your Travel Agent who should be carrying your arguement higher up on the Carnival food chain. An agent's job is much more than selling you a cruise. They SHOULD BE your aggressive advocate dealing with the cruise lines when things go wrong. In my view that's what they get paid for!
I'm not they'll have any luck, but they should approach their District Sale Manager , and then continue up the corprorate ladder to at least try and resolve it.