I was a single mum for 9 years till I met my now dh (and now have ds 7 months so boom goes my child free time!) .. at first I was like you and was very low and didn't know what to do with myself.... I soon began to enjoy it. I don't know if work but I found a part time bar job great as it meant I could pick up some extra hours when dd was away which kept me busy and the social life was good too...
I also went for loads of walks with my iPod and enjoyed the peace. And did a lot of decorating!
I used to feel very low when my son went on holiday with his dad but now I almost look forward to a week of 'me' time. I go shopping, watch whatever I want on TV, meet up with friends, go to the gymn and lie around reading. All the things I can't do when he's home.
I've been a lone parent for 13 years, i used to hate the time that dc were at their dad's. I used to fill the time cleaning, ironing, sorting out cupboards, defrosting freezer & generally keeping busy etc. My friends were a great support but I was the only lone parent in our group so didn't like to be a "burden" especially around Christmas when everyone seems to be having a nice family holiday time. Have you thought about going to the cinema, or local museums & art galleries are usually free & a great place to sit have a coffee & people watch. Is there anywhere you can go for a walk? How about a duvet & dvd day? I remember feeling very isolated when I was without dc, the time used to drag. But Friday will soon be here and your dd will be home. Have you got something nice planned for when she's back?