Is my apartment making me sick?

I moved in my apartment in July of 2010 and in September maybe October i started to get really sick. I would start coughing really bad and i would cough so bad that i would throw up. i would feel sick all the time. Very tired all the time. When i would leave to go to work i would be fine but since i lost my job i am back home again and started feeling sick again. i have been to the doctor and they don't know whats wrong with me.So could my apartment be making me sick. I don't think there is any mold anywhere haven't seen any and i have not seen any water damage.