Windshield fogs up to the point of zero visibility when defrost is on

Before the fogged windshield issue started, there was a clicking noise from the dash area when I purchased this vehicle through private party. After some inquiring and searching I came to the conclusion it might be the blend door actuator. Before I could fix the actuator, I noticed one day the clicking had stopped. Later that evening when I turned defrost on my windshield became fogged up to zero visibility and luckily I was not far from home. I turned around back to house and decided to get actuator the next day hoping that was going to fix the issue. I put the blend door actuator in myself, all back together but the problem still occurs. I then noticed I was extremely low on antifreeze so I filled the tank, and while doing so noticed the seal missing on the cap. So I replaced that. Talking to the folks at Central Point O'Rielly's Auto Parts store, they suggested possibly replacing the thermostat. So now, I have replaced the blend door actuator, the cap on the pressurized overflow tank, the thermostat, filled it with antifreeze and still have the same issue. I notice also that the passenger side barely starts to defrost eventually. And the smell of antifreeze is almost unbearable when defrost is on. Please help. I cannot afford to bring it in or I would! Any ideas on what could be the problem?