I Have A Rattling In My Lower Chest Causing Me

I have a rattling in my lower chest causing me to cough but most of the time it's nonproductive. I cough so hard it makes me dizzy and takes several seconds before I can see clearly. I feel like I need to blow my nose but I can't get whatever is back there to come out. I feel extremely weak and even nauseated most of the time. This started Friday evening with a sore throat and was full blown by Saturday afternoon. What can I do to ease the coughing?