Can a negative thought or feeling bring forth a positive result?

For instance ; starting with the thought, which leads to the action-
C I lost 55 pounds and now I am pursuing my dreams
T If I gain my weight back, I will not respect myself or have as much faith in myself and will not go towards my goals and dreams so boldly
F Worried
A Work out, eat healthy, take correct medication, get enough sleep
R Don’t gain the weight back