First depo shot on jan 14, day 2 of cycle. unprotected sex several times jan 23, negative pregnancy test today. extra sensitive test. odds of pregnant?

< 0.1% (very low): If used properly (1 shot every 12 weeks, and no unprotected sex until 7 days after the first shot if started mid-cycle), then less than 1/100 women on depo Provera (medroxyprogesterone) will become pregnant in a given year despite regular sex without another means of protection. That puts the monthly failure rate at about 0.08%, and you are describing proper use. So, virtually zero chance.