if i am terminated from a job, when i give up my work permit, do i lose my non-immigrant-b visa.

No, but you must surrender your WP to the MOL within 7 days!!!!

if i am terminated from a job, when i give up my work permit, do i lose my non-immigrant-b visa.

Correct, you do not loose a current non immigrant B visa when you give up your work permit; you can remain in Thailand until the permitted to stay date on your current entry stamp in your passsport.

You can also re-enter Thailand on the same visa on any date until the enter before date on your non B visa, if it is multiple entry.

However, if you have a visa extension from Thai immigration, issue on the basis of business, then you must leave Thailand within 7 days of leaving your job.