I think this kind of lack of motivation hits us all occasionally, and this hot weather doesn't inspire great burst of energy, does it?
I think the secret is to have a list of daily tasks you want to achieve. Recognise that the most physically active ones should be done in the cool of the morning, or in the cool of the evening, i.e. walking out in the town, so try and set your alarm clock early so you can make the most of your time and the cool period. Then draw up a timetable of other activies, i.e. 11 a.m. scour newspaper for situtations vacant, 2 p.m. Dust up CV and print off copies, etc.
I know it's temping just to chill out when you have time off work, but if you want to achieve anything, you do need some kind of discipline and structure to your time. Just intersperse the chores with some leisure like like surfing the net, reading or TV, but mark these time limits with a little buzzer to remind you that "Time's up" so that you don't get carried away.
The days ticks away so quickly that the only way we can capture it is to measure it and allocate it. I've had days off work in the past, planned to do so much with them and then just generally wasted them and felt angry about it afterwards. Remember the old Latin proverb: "Carpe Diem". It means "Seize the Day", and that is what you have to do if you want to get anything done.