Let's face it. None of us are always 100% on the top of our game...and that is actually good news.
1. Trust the Bible
"When I was with you I was in weakness...that your faith should not rest in men but in God." If anything of value happens in the Kingdom of God, it is because of Him - not us.
For the sake of Christ, then, I am content with weaknesses, insults, hardships, persecutions, and calamities. For when I am weak, then I am strong. 2 Cor 12:10
2. Is it YOU or the LORD -
Isn't it a temptation to pat ourselves on the back for "such a great lesson I constructed..."? We all felt our "self" creep into the space intended only for God's glory. When I am weak, I have an opportunity to see God work in a way that I clearly know is Him.
3. Confidence in Our Weakness -
If you are weak as you seek to serve, you are in a good place. It is tough to seek to "steal the glory" from God when you are clearly not preforming at your perceive best. Our weakness IS His strength. Your weakness actually may be the best launching pad for His glory.