Period off but still slightly bleeding for 2 days afterwards & now yellow sour smelling discharge?

Discharge : New discharge, especially if there is an odor is worth having evaluated. Most common cause is vaginitis, which can be due to yeast (yeast infection, usually itchy and white, curdy discharge), bacterial vaginosis (can be greenish or yellow with fishy odor) or trichomonis (green, frothy, odor). If you had unprotected sex, trich or other STDs (such as chlamydia) could be the cause and need treatment.