Philippians 4:13

I can do all things (which He has called me to do) through Him who strengthens and empowers me (to fulfill His purpose-I am self-sufficient in Christ’s sufficiency; I am ready for anything and equal to anything through Him who infuses me with inner strength and confident peace).

The word of God is the bases for our confidence in our life and not our circumstances, feelings or thoughts.  We can do all things which God has called us to do because He provides the power to make it through.  Our thoughts and words need to line up with the word and then we will succeed.