Losing weight does not happen over night. Staying or going back in shape takes a lot of effort and time. It’s never wrong to make mistakes while you are staring (or even when you’re already a pro on this).
Being healthy takes one step at a time and it is about starting anew whenever you slip up.
No one is hurrying you to get back in shape. Bear in mind that as long as you are determined to reach your goal, you will eventually succeed. And one more thing, self discipline and control would take you a long way.