I assume you have checked the power steering fluid level??
Low fluid could cause the symptoms you are experiencing.

If fluid level is ok, I think you are correct in thinking the pump is fubared.

Most likely, the pressure sensor was trying to tell you that months ago, and by ignoring that, the pump is now totally stuffed.
No real damage done, as the cost of a new pump is the same anyway.
Some small risk that the steering will suddenly become very heavy while you are driving, so be careful.
If you have never driven a car with broken power steering, it is heaps harder than driving a car with no power steering.
Cars with no power steering are made to be driven that way.
A car with power steering is set up to drive with the power steering working.
When broken, you need arms like Arnie used to have.

Good luck.

PK