Learning to say no

This seems to be a reoccurring issue for me. I simply cannot seem to say no to anyone (well, except my kids, and even then I have a hard time).
Here's my most recent dilemma: The YW are having a ward dinner/talent show/silent auction/bake sale for the girls camp fundraiser on March 11. As a YW board, we have planned it out and gotten things assigned. My part of it was to work with the 1st counselor on the silent auction part. I was excited. Yes, it's a lot of prep work...getting items, making auction sheets, tallying the info that night, collecting money and making sure everyone receives their items. But, it's something I could do, the lady I was doing it with is super fun and I was looking forward to a behind the scenes kind of job. :)
Well, last Sunday we had a board meeting and somehow I got assigned to do the decorations. I didn't want to do them, I tried to voice my "negativity" about doing the decorations, but everyone there had it in their heads that I was the one to do it, so I got it. That's fine. I'm going super, and I mean SUPER, simple. The other leaders are ok with that, so that's the plan. They also want to do something in the talent show portion of it as YW leaders.
I get home from my meeting and Steve informs me that the bishopric has been asked to do something for the talent show, they want the wives to be part of it also, and the bishop thinks that since I've been to girls camp a lot, I'd be the perfect person to write the skit and plan it and get it all ready. Add that to my "to do" list.
I'm also up to my elbows in preparations for the items that Becka and I are getting ready for the auction. I'm working on two fairy costumes (tutu, wings, headbands and wands, three of those "We Believe" picture frames that I posted about a month ago (frames need to be painted, flowers made and glued on, etc), I'm doing a bunch of hair clippies and headbands which I haven't started, Becka's making a scarf, I'm decoupaging a treasure box, framing a few of our photography prints and going through my stuff to find anything else that might be able to be auctioned. We are making cookies, cinnamon rolls and a fancy cake the day of the auction.
The next thing I know, the YW president has asked that I take the Beehives around to athletic clubs and restaurants in the area one afternoon and see if they can get any donations for our auction. So that would mean me, up to 6 11-12 year olds and my other three kids driving all over town with me most likely being the one doing the talking. First of all, I have a big car, but it isn't big enough for that many people, so I'd have to find (and possibly pay for) a sitter for Jake and Rachie, second, I don't have the time or desire to do something like that. I did finally tell them that I wasn't doing that. Somebody else's mom who isn't in the YW presidency can do it.
So not only do I have all of that stuff to do, I'm trying to take care of my family, get kids to their various activities (Jake has indoor and outdoor soccer practices and games, and an after school sports class once a week, scouts on Thursdays, Becka has bowling every morning at 6:15, Mutual on Wednesdays, Rachie has swimming twice a week), get caught up on the never ending laundry and I've been going through and de-cluttering my office/craft room so that things will be nicer. With Steve in the bishopric and him working so far from home, I rarely see him, and when he's here I feel like I'm either working on some project or running to another meeting and not being with him. It's just too much for me. I know some people wouldn't bat an eye at that list, but I'm still in a place with my depression/anxiety that I don't want to push it too far. I want to feel good and be happy and take a tiny bit of time to help myself feel good too now and then. Is that so wrong?
So, while I am proud of myself for finally saying no about the one task, I wish I had the good sense to tell them to only give me one or two things to do instead of a bunch of things. I'd cut out the auction items, but Becka needs those to help pay for camp ($135!!!!), and I had already promised to help her with those things before I got all the additional assignments. I must let people walk all over me, since it seems that some of them are inclined to just do it automatically and dismiss me when I try to object. One day soon I'm either going to surprise them all by a) refusing to do anything, b) freaking out on them when they start dumping stuff on me or c) having a nervous breakdown. :)

So, if you'll excuse me, I have to go feed the baby and then finish painting three picture frames, a treasure box and two donation cans...