Today I was "that mother" with "that child"

OMG. What a day. Rain + Chuck E. Cheese = lots of hyper kiddos. So, Miss K and I met Miss E and her mom at CEC for a little fun. We had a good time. They girls were on their best behavior except for one minor incident involving the mini merry-go-round. So, after we leave, I needed to run to my favorite store...Hobby Lobby. I needed to return a couple of things and pick up some felt for a project I am working on. Well, she started doing the "peepee dance" while I was standing in line. So, I finished and took her to the potty. OMG. She lost it. I pulled her panties down and she would arch her back so that I couldn't get her to sit on the seat. And crying. HUGE tears and SCREAMING. She kicked me and was screaming "NO!" We were using the restroom at the front of the store, so I know that everyone and their mother heard us. I finally told her that if she wet her pants, I was going to spank her. We went through this whole thing at the post office on Tuesday and she did wet her pants. So, we walk out of the restroom and EVERY person in the check out line is looking at me. Miss K is still screaming. At this point I am trying to figure out why she is still freaking out. She starts jumping up and down, stomping her feet and screaming. Again....everyone is looking at me like I am the worst mother in the world. I calmly picked my screaming, kicking child up and removed her from the store. We get outside and she is even more upset. She doesn't want to go home. She wants to go back into the store. I told her that she had to stop crying first. MORE crying ensues. I pick her up and carry her to the car. She cried the entire way home. I mean....WAILING. She cried so much that by the time we got home, she was hoarce. We came home. I told her to go upstairs and go to her room. More crying. Screaming. Mommy needs a stiff drink. After about 30 minutes, she comes out and apologizes to me. And...to make it even worse, the lady who does the returns at Hobby Lobby was a complete witch to me. This is the second time I've dealt with her and both times she has made me feel like I have done something wrong. Today, after everything that happened, I've decided I do not deserve to be treated like that. I'm writing a letter to their office. Before you say, "talk to the manager", the issue today also deals with the manager. ARG. I'm just irritated. Totally. Irritated.