My question involves landlord-tenant law in the State of: Chicago, Illinois

I live in the city of Chicago. I have been complaining to my landlord for months about bedbugs, my bathtub, and other things thats wrong in my apartment. I have documented every call I have made. I took pics of the bedbug bites. A neighbor asked my landlord, " Who lives like this"? And his response was, " Poor People". This has saddened me. I also have had to go to the doctor because I no longer sleep in my bedroom. I am sleeping on the couch, and the hardwood floor in my living room. Is it possible I can sue my landlord?, since he doesnt care I have sleepness nights, and backpain, and he doesnt care what his tenants have to go through. Also can I withhold his rent because of all the problems I am having?