Big Let down!!!

Well today was our 3rd weigh in and I was not very happy with the results. I lost but only .4 pounds. I was really upset because I had worked so hard this week. It seemed like today was going to be really rewarding. I ate breakfast because I was confident in the way my week had gone. These are the times in the past that I have wanted to give up because it seems like no matter how hard I work I get no results.
 I went into this week thinking I was going to slack alittle but I didn't I even went to the gym when I didn't want to and even when I didn't feel good. I was happy I was doing weights with the cardio and actually sore but feeling like I was really motivated and all that is kind of gone now. See this is what it is like to be fat, it's so much easier to give in and just stop and stay the way I am. But at the same time I feel like I am giving up on my son. Today I preached at him because while he was at his fathers they had Chinese. I have asked them to try to help encourage Xavier to eat better and make good choices and then he gets Chinese food. I feel like if I give up and don't keep changing my life choices I am showing my son that it's ok to just throw in the towel when things get hard. Honestly that is exactly what I have done in the past. I am not sure what is so different then the 8,000 other times I have tried to lose weight but really looking at my son and realizing I am the only example he has to show him how to make good choices in all areas of his life. I have given up so many times before I can't now. If I do I not only fail but I fail him. How can I do that to my son??!!! Where do I get the energy and the motivation to continue on. I don't know but I have to do it!!