I'm 13 and have been given Co-codamal terrible sideaffect?

I Feel horrible, Nausea, Vomiting, like i'm Travel sick, and i've looked through side affects and i've seen theres side affects of fainting, bleeding gums, nausea, vomiting, dryness of mouth, easy bruising, easy sensitivity, easy shock it's horrible, it's like it on and off, but surely can it be aloud that a doctor can give a 13 year old such a drug, i don't know what to do please help.