aww dont be too disheartened - you wont lose weight every week. I noticed that you are doing 'my own' diet - maybe its worth trying something slightly more ordered?
For me, I've tried to do it by myself loads of times but end up cheating. If there are some clear rules/guidance, that can really help. Doesnt need to cost a fortune.. for example you could try calorie counting (myfitday is free and will help you with this)?
This site is also brilliant for motivation - have you had a look on the before/after pics? They always give me an extra boost if I'm feeling like giving up..
Best of luck x