You are being used. The hardest thing I had learn was to say "No" to people who wanted little things done for them. Because I had a sewing machine, because I knew how to sew.
I'll show you how to do it but won't do it for you.
I even had a women tell me I was be unchristian when I said I would not re-upholster her couch cushions. "It's just a pillow case." I turned it around and asked her where in the Bible it said "thou shall re-upholster thy neighbors couch."
It's very freeing when you learn to say 'No' without guilt. the first few times are the hardest, but more you say it, the less guilty you feel. If you laugh it off as if they are joking it helps a little too.
I understand how you have to be friendly towards spouses of your dh co-workers. It's amazing how some people think because your spouses work together you should be best friends with them for no other reason. Gently push her away, be busy when she has a requet stuff like that.