4 Should Have Been 5 Miles

I was going to do my speed training work out that I have done the past two Tuesdays, but I just couldn't do it. On Sunday Evening I noticed that I was getting a cough and it just kept getting worse and worse. I decided to still go to the gym because I don't want to skip any workouts. Well I did the first two miles fine, rested three minutes while getting on a new treadmill, and then did mile three at a 8:20 mile pace. Well, this was a bit much for my lungs. I was trying not to breathe in deep because that would cause a major coughing spell. It was just really difficult to get through that mile and at the end of it my chest was burning!! The lungs are not in great shape right now. So I did a fourth mile at a 9:40 mile pace and then called it quits. My back hurt and I couldn't breathe properly. I have been sick now for over four weeks and this newest bout of gunk has me worried. I really need healthy lung for the race in a mere 17 days!!! I'm pretty sure tomorrow I will have to rest because I can tell it's only getting worse!!!! So much for training for a marathon keeping your immune system up!!