Out of control

So I have been doing weight watchers for about 6 months now and have lost about 25 pounds. I still have 5 pounds until my goal. I was so close and them this weekend just ruined it for me. I am so upset at myself! I had a birthday party on Saturday I ate just the veggies but used some of my flex points dor cake and a few chips. That day wasn't too bad but then the next day Joe made fresh cookies and of course I had to eat them. Dessert is my down fall. I could not eat fries for the rest of my life and I would be okay. When it comes to chocolate or dessert I can't help myself. Then on Memorial Day we had a going away party for Alex and Olivia :( and of course there was lots of sweets! They were so good I couldn't stop eating them. I was so stuffed but I kept on eating them. I am out of control! I think I gained about 3 pounds this week. It suck because it takes just 2 days to gain 3 pounds but it takes a month to lose it again! I am so sick of thinking about food all day. I feel like it runs my life. I have been working out for over a month and my weight loss has gone from losing 1-2 pounds a week to 0-.5 pounds of loss a week! I was doing better before I joined the gym. I don't want to quit because my main goal is to run a 5k in October so that is what I am trying to focus on right now. It is my first 5k ever! I am very excited but at the same time very upset with myself for not having any self-control. I have to keep reminding myself that it is a life style change not just a "diet"!