A lot of people on this site has great success stories! What you don't see though is the struggle and set backs everyone has "behind the scenes" sort of speak. I'll use me for example, this time around I've lost 40lbs, sounds great? What you don't see is that I've lost and regained this before and there are weeks that my eating habits SUCK and my weight goes up instead of down. It's easy to forget that everyone has or is having the same struggles and thoughts as you are when you are not reminded of it constantly! I have been where you are, I would start eating healthy and working out and after a week of little to know progress would throw in the towel and go order 2 large stuffed crusts pizza's!
The first 2 weeks for me was the absolute hardest! As a fast good addict I was dealing with what I call "withdrawal" from all my favorite fast food places. I would crave them! Almost or as bad as I craved cigarettes when I quit smoking, that's how much I wanted them. All the cravings for chips, candy, fast food and junk would put me in a crappy mood and make me wonder "why am I doing this?". To combat this I wrote out a list of things I looked forward to when I had lost the weight, things like my muffin top not being pinched out by my underwear, buying smaller clothes etc. It served as a constant reminder of why I was getting healthy.
The weekends are hard but I attempt to view them as any other day instead of singling them out as "special" days. Of course this doesn't always work for me either, its all about learning to get back on plan after you have screwed up! Take this Sunday for example, I went over to my moms, ate a healthy dinner and should have stopped there. Did I? Nope! I went on to eat 2 cookies that I later read were 370 calories each, 2 pieces of sourdough toast with margarine and a huge piece of rice crisps my mum made. Huge fail on my part, I ate almost all of my daily calories right there in one sitting. I let myself feel bad about it for an hour, then moved on and Monday was back on track completely!
Just try to take it one day at a time, when you get up think about what you will have to eat at breakfast, lunch, dinner. You are more likely to make healthy decisions if you put some thought into it at the beginning on your day when you are less stressed then at lunch there is no guess work!
Good luck, you can do it!