Gosh, I sort of know what you mean. Part of it is, I think, just accepting that you do look different from how you did 10 years ago. But as you recognise, you do have to like how you look now.
You say you don't like your hair. What about changing your hairdresser? Ask a friend whose hair you like where they go, and then go to see the stylist for a consultation before you commit to anything.
And make-up. Have you ever had a beauty consultation at, say, Bobbi Brown, who are supposed to be very good? Or, if you have one near you, you could try a Space NK where they have lots of different brands, eg, Mac, Nars, By Terry, Laura Mercier, and usually helpful assistants willing to spend time with you to find a lipstick or whatever that really works for you.
On a similar note, although you don't mention clothes, maybe you could try a personal shopper at John Lewis, Selfridges, Gap or Topshop, depending on inclination and budget. You don't even have to buy but you might get some good new ideas.
I really know what you mean about struggling to fit the exercise in - but can you do a DVD in the evening after your DC are in bed? Or, if Your DP or someone else is around to look after them, go jogging now the evenings are getting lighter? If jogging isn't your thing, what about swimming? Lots of pools open late into the evening.
One last thing: I bet you don't look nearly as bad as you think you do. We are all our own harshest critics.