amoxicillin and vomiting

okay, i'm 13 and i start on the whole "8 pills a day for a week for stomach ulcers" thing. i've read up and done my homework on amoxicillin (which is the antibiotic that is included in the package), and i'm afraid that i'm going to be experiencing nausea and vomiting all the time. i'll be in school all week and i don't really fancy tossing my cookies randomly throughout the day, or running to the bathroom every half hour. i hear the headaches are pretty bad too... is vomiting the most common side affect? is there anything i can do to prevent it or to make the nausea go away? if i take the medication with food will it these side effects? thanks!