Larry, I'm 63.5 years old and got laid off from 100k/year job last year. If I don't find a job making that kind of money again will my social security benefit estimate go down before I retire at 65?
Your retirement benefit amount will be based on your highest 35 years of wage-adjusted earnings (https://www.ssa.gov/pubs/EN-05-10070.pdf). Your benefit rate won't go down if you stop working, it just won't get any higher. The only way that your benefit estimate would go down is if projected earnings that fail to materialize were included in calculating the estimate.
You may want to consider using the maximization software available on this website to calculate your benefit rate and determine your best filing strategy.