A good place to start is to read through the sticky "Don't start your claim unprepared" at the top of this forum.

The standard for approval is that you're unable to perform any job, not just your former job. Can you do a job that does not require standing? Also, you say you're unable to stand for more than ten minutes, but has one of your doctors documented that (along with any other functional limitations)?

Just to clarify it was SSI not SSDI you applied for? You didn't really make it clear when you stopped working?