I am always ill. always catching bugs and colds, always tired and feel drained, what could this be?

Tiredness: Essentially needs a doctor assessment for specific diagnosis and advice. Here is some UK based general information on tiredness and possible causes. http://patient.info/health/tiredness-fatigue

Always ill.: Could be some many things I could not list them here. What you need is a detailed medical history that includes your family, social and work history. Then a careful medical exam. This is not a problem for online medical help. See your Dr. over there or do a 2nd opinion so you and I can chat to see what is going on.