Heart break for a mother

Brayden and Katelyn had their well child checks today. Our doctors office relocated to another town so we had a 20 minute drive. Brayden brought his new DS he got for his birthday and Katie was happy in her car seat like normal so off we went with a pleasant drive. We got to the doctors office right in time for the appointment and they were running a few minutes late so the kids played so nicely on the floor. They had the coolest toys in their brand new office and I couldn't be more proud of Brayden including his baby sister in their play. The nurse called us back and they even got to bring a bunch of toys back with them. We were all playing together waiting for the doctor. Brayden barefoot (waiting to be weighed and loving every minute of that) and Katie in her diaper (loving every minute of that herself). When the doctor came in the two of them were in hog heaven. Katie jumped in our doctors arms and jabbered up a storm while Brayden tromped around playing occaisionally giggling. Everything went so well for both of them. She kept commenting on how well the two of them played together and how well they seemed to be doing. Life was great then the appointment was near an end and the nurse came in and asked me to hand Katie to the receptionist so I could hold Brayden. I knew what was coming. The two of us had been secretly making plans so Brayden wouldn't be so nervous. I popped him up on my lap and had to pull his pants down exposing his leg. He finally caught on and screamed "I don't want a shot!" Here he was having the time of his life so happy and then his own mother has to hold him down to get stabbed TWICE! I know it is for their own good and I have had to do this so many times but I always feel I am betraying my poor kids luring them to the doctor for their yearly poke. Brayden cried. Not out of pain, more like how could you do this to me? And mom how could you let them do this to me? I hugged him got his pants pulled up and tried to help him focus on the chocolate donuts I promised him for being such a little man. I asked him to calm down so he didn't scare Katie and he sucked it up best he could so she could come in for hers. My baby sat there gabbing at that nurse clear THROUGH the first shot before the look of betrayl came across her face. I felt so bad to see my children so happy, having such a great time playing and interacting with all the office staff just to see them so quickly offended. I know it is for their own good, but doesn't it just break your heart having to betray your children so?