Hi K. -
YOu've got lots of good answers here. I can share what has worked for me from my own personal experience. My kids are now 13,10,7 (and we still wrestle with this - they do demand a lot of attention!).
When they were younger, I was working at home (still do) and not only needed time for personal stuff, but also needed to get work done. I found that letting them do something together that was really out of the ordinary keeps them busy for a while - like they'll build a fort in my dining room with blankets chairs etc and then sit in there and do puzzles or read. I have them agree to put away whatever they take out before they begin, so that keeps them busy just a little longer, too, and I don't have to worry about another project when they're done!
When my youngest was home and the others were in school, I used to set up a little desk for her next to mine, so she could "work" alongside me. I got my work done and didn't feel guilty about ignoring her - one of my biggest reasons for working at home, of course, was to actually spend time with the kids!
The same principal works for scrapbooking. I'll give the kids their own notebook, paper, and old photos and they'll scrap alongside me.
Now, sometimes, I realize - you really just need to be alone. It is ok to tell your kids that. I was one of 6 kids (all within 8 year age span) and my Mom & Dad used to say every day from 7-9pm was "quiet time" - we had to go to our rooms and read, do homework, draw whatever - but no talking, no music. I complained at the time but totally understand where she's coming from!
We have quiet time sometimes too - not as a routine thing but when we really all need our space. My youngest doesn't like to be alone as much, so sometimes we'll snuggle up and read books until she falls asleep. And then I can read by myself for a while.
Bottom line though - you do deserve some alone time for whatever reason and purpose. You shouldn't have to scream, but you will have to be clear and firm with your husband and kids in letting them know what you need.
Best of luck,
D.
(editor, Piedmont Family Magazine - www.piedmontfamilymagazine.com)