last week I drank about 2 bottles of robitussin (the liquid). I couldnt tell yu how much the dose was.. but every 20-30 min or so I would suddenly become very itchy around my entire body. Like a very intense itch an it felt like my skin was being ripped off of me in the process of scratching. I also could only really see like a blur of colors. is this normal or did i overdose? future reference for next time and I would like to know what you all felt