Never Give Up

Just when you think that you are in cruise mode with your goals an iceberg comes along.
"I am the Titanic, I am unsinkable!"
Er, no, that iceberg is going to rip you open from stem to stern.
Ok, perhaps that's a bit melodramatic, but that's how it feels when you fall off the rails.
"I'm a loser. It's all over. My diet/exercise plan/goal is RUINED!"
Have courage. Very little is completely wrecked by one or two failures.
If you look at a plan over a period of months or years, the blips of falling off the rails won't even register. The big thing is to keep at it. Never give up.
You cannot throw in the towel because there is no towel!
Keep your nose to the grindstone, and you will achieve that goal. One or two stumbles do not define the journey. They do not turn you into a failure. The only way you can be a failure is if you decide that you are a failure.
If you simply stick at it and refuse to give up you will get to that goal.
Stick to that goal. Success is there if you grab it.