Dont worry one bit about this. You are going to be completely fine! Your sis got sick because of a combination of too much medicine and the congestion. I am sure of it. If you get a cold, stay calm, you will be fine...just be careful on how much medicine you take and like katsamsmom said, avoid the dairy. Isecond that on the fact that it will make you n* when you arereally congested. Relax and know you are going to be fine!