Re: there is yellow mucus in my nose. do i have a sinus infection?
Smith is correct in his answer. Also, if you have the "color" all day long, then it's more likely to be an infection. Many people have colored discharge in the AM for example. Face and/or teeth pain is a sure tail sign as well as a fever. If you have all three, you've got a sinus infection for sure.
Also, if it's determined that you do have an infection at some point, it's critical that you are antibiotic compliant...Meaning finishing all your meds. Many patients stop taking the antibiotics around day 7 when they feel better and then the infection returns at some point, or mutates into some other bug. Infections that aren't successfully cured in the sinus area can often form polyps and they can only be removed via surgery.
Good luck and hope you feel better.