Do I have the right to be upset or am I just over reacting?

A new friend noticed my son playing with some tractors at a park we visited with her and her 2 kids in October. At the time she said "oh good, that's what I am going to buy him for Christmas so don't buy him any tractors". In December she came over one day with her Christmas list and a toy magazine for her kids and proceeded to tell me what she was buying them and then showed me a stuffed toy that you could purchase for a reduced price by spending "x" amount of dollars. She then said, "Oh this is what I am going to buy your son". At the time I didn't have the heart to tell her that I really didn't want her to buy my son anything as I didn't want to start getting into that with her kids every year. She invited us over for Christmas Eve and I ended up buying her children a $50 gift card from Toys R Us. I felt obligated to because of our previous conversations that she was buying my son something. I left the envelopes on her counter in plain sight with her girls names on it. (cont)