Will having the flu impact on my running performance? Ask Coach Parry 9

Today’s question comes from Lennard Van Wyk:Hey Lindsey, just would like to ask your opinion about my training: I am currently running 6 days a week. I average about 70-80kms per week. I take all runs easy at 5:50 min/km. I only push hard on Tuesdays when we have time trials, my times are 39min for 8km. Then weekends I only run on Saturdays, and rest Sundays. The Saturdays are long runs, I combine a half marathon with some extra kms. I also run them relatively slower. Since start of January I have never done less that 25km on a Saturday, and I have done 2 runs of 30kms prior to the Deloitte Marathon.So what I want to know is, yesterday went really bad, I was just so tired at 19km, I had no energy. I pushed on, and managed to finish 4:41. But this was quiet a struggle. Now I need to add that two weeks ago, I had a little bit of flu, nothing serious, and last week, the week prior to Deloitte, I didn’t get much sleep as my son was born Sunday a week ago. So should I blame the lack of sleep and the flu, for my poor performance, or am I doing too much kms?