Don't second guess yourself
How do you say that in Spanish?
3 Answers
Maybe... No te dudes... or Ten confianza en ti mismo. I don't like these translations as much as the original expression, but some things are just more exact in the original language, be it English or Spanish.
How about ... no dudes de tí .... or no te des más vueltas....
Or maybe; No dudes lo que hiciste la primera vez.