I was the same way for awhile. I would try to lose weight but the second I was set back I would just ... fall apart and not be able to continue on my goal. This time for me is different, I told myself that I have no other choice than to lose weight, I refused to weigh more than I did at that very moment every again and got to work.
I've found that if I plan on working out at the end of the day that I never get to it, which stands in the way of reaching my goals as well, and I would do the same thing as you -- find myself doing nothing instead of exercising.
Try making a contract with yourself and start by making smaller changes first. Once you see the weight start to come off, take that as encouragement to make other changes and continue from there. Whenever I would start making massive changes from the beginning I would find myself more easily discouraged than when I started by making small changes, and once they became a way of life, making more.
For example, last November I went to Italy and decided to completely change the way that I eat. I started cooking for myself, cut most fast food out of my diet, and stopped drinking soda. Once those changes became normal, I started changing my diet to be a little healthier, and cut out most white flour and candy. Again, once I made these changes, I adjusted again ... this time I started working out 5 days a week, and so the cycle goes on. That way the changes that I were making were more of a way of life than anything else and it REALLY helps me not get discouraged.
You are in charge here and you CAN do it. I know how hard it can be and how easy it is to become discouraged but once you get used to sticking with it, the changes you make become changes to your lifestyle and before you know it, everything is different.
Best of luck! And signing in and being an active member here has really helped me stay motivated with sticking to my plan. Join some challenges! It might help.
