It's okay. Sometimes I think kids grow up in spite of us instead of because of us. Here's one of the times I had a "horrible mother moment." When my oldest was a toddler, we used to throw really soft, plush toys at her. She thought it was hilarious, and we delighted in making her giggle and squeal. Well, fast forward six months when she's getting in trouble at church and at daycare for throwing toys at other kids (and not just soft, cuddly ones). It was so much fun at home that she just didn't understand why her poor friend Lucy didn't want a Thomas the Tank Engine in the nose. We were fortunate that she's a verbal kid, so we could explain it to her and "fix it" quickly.
At any rate, sometimes we screw up some things for our kids. If we take it in humility, it is a learning opportunity for us as well as our children. Most of the time we see parenting as raising children, teaching them how to be adults (eventually), but God gives us children so that we can learn as well. I've learned more in the last 4 years as a parent than I probably did the whole 25 years before that.
And... maybe it wasn't the paci. Plenty of kids use a paci for that long, and most of them probably don't have the same issues as your kiddo. Maybe it wasn't you. =) Just a thought.