I have the same problem mate. Full time job and 4 hours study course the afternoons. Likewise, my home is a mess, I just don't have time to tide it up. I come home from work, cook something quickly, wash the dishes as fast as I can, and then go to the college. My room is a mess during the week - not dirty or smelly though - just messy, clothes thrown around etc. But as you say, that affects my productivity and motivation. The weekend when I'm off, I clean everything and make the house spotless, which makes me really happy and gives me energy to study or exercise. Until Monday when the downhill starts again.