AB- blood type very rare

I have AB- blood. I read that this is a very rare blood type. Also that ab- blood types have a weak immune system and need a daily supply of vitamin C. I find this to be true because I get the flu or some form of a bad cold at least twice a year, where as my siblings next to never even get sick. I also think that we are a rare breed of people. I was always in a class of my own.....am I the only one?? Tweet