About a week ago, I went to a clinic to get checked out for what I thought was a two-week old cold/sinus infection.  I've had a history of sinus problems, so when the doctor told me it was a sinus infection I was not at all surprised. She told me to take amoxicillin (penicillin) along with some regular strength Mucinex.  A few days after I started taking the meds (2 times a day) I developed a rash around my labia, and both my nipples (only occurred one day) and vagina had a yellow discharge.  Is this due to the medication? Should I finish my dosages?