There are times when I'll be having a bad day and am in bit of funk...
Vibrato is inconsistent, intonation is suffering, the whole 9 yards..!
The reality is that those days are going to happen. You're going to feel like giving up, but that shouldn't get in the way of pursuing your dreams. This should go for anything in life. When things get difficult, you don't want to just give up, do you? Often times the best things in life are the most difficult to achieve because they're the most rewarding. Don't let a couple small things get in the way of the bigger picture. Keep things in perspective.
Life is tough to those who dream. Keep doing what you're doing and those little things will add up in big ways!