I totally know what you're going through. I do this all the time. I lost 30lbs and have maintained it for the most part, but now I want to lose 20 more and i keep gaining and losing the same 5 -10lbs.
I go through times where I don't care and times where I try really hard and do well...once again...just to gain it back.
I was student teaching and going to school last year full-time so it was really hard to even think about trying to focus on losing weight and absolutely no time to workout because i was so exhausted at night. There were many times I would just eat out and not care, but then one day I'd wake up and everything would click and I just started to try to make a plan to work within my situation. I took a little extra time to plan out what I would eat everyday instead of leaving it up to chance. I made myself go to the store and buy healthy food to bring my lunch with me and healthy non-perishable snacks so I wouldn't lose energy...granola bars and big bottles of water were my friend
I think losing weight is hard no matter what and, for me at least, it is a never ending cycle of being motivated and being disappointed in myself. ****the important thing is that I never ever ever ever give up completely***** even in the times when I knowingly eat really bad, I tell myself I can never give up on trying to lose. the next day i have to try again!! (sometimes its not the next day but in a few days or the next week, but i eventually go back to being conscious about what i eat.
whoa, sorry so long...i just really relate to this topic
hope i've helped