Dont feel down on yourseld after you eat a little bit to much. Ive been trying to loose weight myself and i have to admit to you, every now and then you need to indulge. Not every day but you should totally treat yourself. Make goals, for ex..loose ten pounds and then treat yourself to your favorite meal. No ones perfect, theres going to be many more days down the road where your going to over eat. Instead of feeling bad about it,wake up the next day and go harder in the gym and get back on track. You got this girl!!
Sounds like you need a better motivator. Perhaps your health or a nice outfit you love and can't quite fit into yet would do the trick. It'll give you the boost you need to not take in extra food that'll make you feel guilty.