Oh @TheGhostofGlumy, what a tactless thing for your DF to say! I can completely empathise, when I lived on my own everything was neat, tidy, clean. everything had a place... now it's a constant battle just to keep on top of things and stay sane(ish), frankly. I was only today bemoaning (to myself!) that I thought the house would be in a better state by now, but I have realistically six years' worth of crap to go through and try to improve 
One thing that has helped - apart from the DC being at school, which has finally given me some time to tackle everything! - is buying some new storage units/ bits of furniture to improve storage options. When I say new I don't even mean Ikea-price new, it's all second hand, but we desperately needed another chest of drawers, desk, bookcase and shoe rack... any chance you could have a look on ebay/ Facebook/ in charity shops to do the same?
And apart from that, I'm physically still a mess
I want to start exercising and eating healthily - just feel like I have a mountain to climb in the sense of sorting out the house before I can even think about that! Which is probably silly but I have a real mental block about it.
Hope you are feeling a bit better now but I agree, it's very hard when your DC are small, particularly if you very rarely get a break from them 
(It's me Ruby by the way, just trying a new username!)