Not to worry you (you are already concerned, obviously, duh), but are you talking about yellowish discharge directly from your vagina, on your vulva,, or just indirectly on
your panties? Reason I ask is that if it is on
, it is probably okay, since our vaginal secretions oxidise and 'yellow' outside our bodies as they dry. In that case, you may just have increased vaginal or cervical mucous for some reason.