Posted: 13/04/2014 at 19:02
As booktrunk suggests, could be a nutrition thing.
Slowing down a bit might help - could you hold a conversation while you're running? If not, definitely slow down.
It's probably worth sticking at 5k for a while, repeating the last week of your programme. When you can complete a 5k run without feeling shattered, that's the time to gradually increase the distance.
Good luck and stick with it