Well done Strawberrybelly! Keep going, trust the program! Regarding knee pain, I got knee pain for the whole of the first 20 or so runs in C25K. Looking back, it was mainly due to me being unfit and as I got fitter my knees felt better.
Do you listen to the podcasts or use the app? I listened to the podcasts and these give you various tips throughout about things like foot placement when running, head and shoulders movement, general stuff about how you run well and without injury. Some useful tips I found.
bontingthepebble - could you be using 'it's too hot' as an (invalid) excuse? It's not too hot to run. Humans are evolutionarily designed to run long distances, in the heat if necessary. Your body can do this. Even in 28 degree heat or whatever.
My BMI is 30. Today I ran 10K. In fact I run 50K a week, every week. I started W1R1 of C25K having never run before on 6th April - around the same time as you - when my BMI was 35.
It's not too hot to run. Wear shorts, a vest and a hat. For an under 5K run that you'll be doing, you probably won't need water (Just a big drink when your done and home), but take some with you if it will help you feel more able you run in the heat.
Everyone has a bad run every now and again. If you've not run for nearly a week, that will be why today was a bad run. Don't dwell on it or beat yourself up about it. You understand why you struggled today, so go out again tomorrow, or the next day, and try again. Give Week 8 a few goes and once you complete a run fully, do 2 more at that point. If you do 3 or 4 runs and complete none, I'd be inclined to go back to Week 6 with the 3 different runs leading up to a 25m run. Then moved on from there.
You really for need to trust the program though. A 5 day break will set you back. Try your go out at least 3 times a week, even in the heat. You can do this!