Have to get the leftovers straight in the bin!! (I can't trust myself with them so the best thing is to get rid immediately.)
It is hard , I do sympathise, but you have to be more strict with yourself than ever before (I had to kick my arse into gear repeatedly and still do).
I fully believe you can do it! Maybe get hold of something nice in the next clothes size down and try and shimmy into it each week...it needn't be expensive.That's what I have done to keep me focused. Also, I allow myself to be a bit more relaxed about treats one day a week, it helps me stick to the rules and keeps the metabolism pepped up.
Also exercise when you can..even dancing around while you hoover or lifting a couple cans of beans doing a set of bicep curls.
There has been some excellent input for you from others here so just wanted to agree with what's been advised and send my love. It's going to be a long road, these healthy new habits are for life so please don't panic you are failing. There is no failure, only learning x