My sicknesses won't go away?

This all started about 10 or 11 months ago when I got ringworm. I went to the doctor and got some cream for it and it seemed to go away fine, about a week later it was back and nothing I used would cure it. I still have mild ringworm patches today. Then about 6 months ago, I got a sinus infection. I took medicine for it and it seemed to be going away. Then in came back a few days later and nothing would cure it. I still have mucus build ups and post nasal drip. Then about 2 or 3 months ago I got pink eye, I got drops for it and in just a day or two, it was completely gone. Then a few days after that, it came back strong. I kept using drops and it seemed to go away. Besides in one eye, which still bothers me today, is occasionally itchy and very slightly swollen. Nothing is going away. Maybe all of these sicknesses were misdiagnosed? Perhaps I have a very weak immune? One of my eyes is slightly smaller than the other and it's very upsetting, I look retarded and I have for the past few months. I just don't know what is going on and frankly I'm fed up with it. Please help.