Is there something someone said to you, a place you have been, a sound or song you heard, a person you know, etc?
What will fuel you to fight beyond that initial muscle burn and mind SCREW that will EVENTUALLY come when you're about to achieving that SOMETHING you NEED in order to FEEL alive?
Think about it...seriously.
For me...the first thing to come to mind are the kids and adults going through Cancer treatment that cannot do what I can. The movements I can with the force that I can!
I think about them and they fuel me!
When I am about to quit on a set of repetitions...when the burn hurts beyond comprehension...I PUSH!
What is in you helping you PUSH!?