The Lord God Almighty tells us to be strong and be confident in him, he tells us many times to look to him and be strengthened.

Be strong confident and of good courage, for you shall cause this people to inherit the land which I have given to your fathers. [Joshua 1:6] Only you be strong and very courageous that you may do according to all the law which Moses my servant commanded you. Turn not from it to the right hand or to the left, that you may prosper wherever you go. [Joshua 1:7] Have I not commanded you? Be strong, vigorous, and very courageous. Be not afraid, neither be dismayed, for the Lord your God is with you wherever you go. [Joshua 1:9] The only way you are going to be strong and not discourage and depressed is to meditate on God's Word day and night, and to allow the word to do it's perfect work in your life.

Why are you cast down. O my soul? And why should you moan over me and be disquieted within me? Hope in God and wait expectantly for him, for I shall yet praise him. Who is the help of my countenance, and my God! [Psalms 42:11] [Psalms 43:5]