Can Flu Or Its Medication Cause Blurred Vision And Vomiting?

I was just told by a doctor I possibly had the flu and was prescribed tamiflu for it as well as a cough medicine with codeine. My question is that while I was at school i got very nauseous and went to the bathroom, before i even got to the bathroom i got blurry vision and then i loss all vision in both of my eyes for a couple of minutes. I had someone help me to the bathroom and my vision started to come back and after i threw up my vision returned to normal. I was wondering is this normal symptoms for a flu or a side effect of either prescriptions.