"lay off" is a verb. "lay-off" or "layoff" is a noun.
1. "I was laid off."
2. "Since there's an economic downturn, there have been many lay-offs/layoffs."
3. "Tommy worries so much that one day he will be fired (from his company)." -- "from his company" will usually be redundant.
4. "No worries."
When you quote a