Whats wrong with me :/?

My immune system has been unormally crap this year! Had swine flu twice [they misdiagnosed it&didnt give me tamiflu the first time] bronchitis, flus, food poisoning. Am very healthy [exercise, food-wise, take vitamins and omega 3 tablets daily] Went to the doctor to do urine&blood tests and it came back normal. What could be up?