Sinus infection or something else?

So I take Amoxicillin for my sinus infection. My tooth pains,sore throat and coughing are all gone. I have been taking it for 7 days.I talked to my neighbor who happens to be a nurse and she said that the medicine could cause me to get sick without food and some of the fluid of my ears are draining so that is why I am having stomach aches .I don't know if this is really the case since I still feel sort of dizzy and my tousles feel like they are swelling up again, and my stomach seems to be bloating and cramping .Can someone please tell me whats wrong with me?I don't seem to have a fever.