John 21:17-18–He said to him the third time, “Simon, son of John, do you love me?”Peter was grieved because he said to him the third time, “Do you love me?” and he said to him, “Lord, you know everything; you know that I love you.” Jesus said to him, “Feed my sheep. 

Some seasons of walking with the Lord can be so difficult, that you can question whether or not you love the Lord at all.  I believe that is a healthy examination to have, as opposed to whether the Lord loves you at all…(2 Corinthians 13:5)
The context of this passage is famous for Jesus appearing to the disciples after His resurrection to have breakfast with them.  It is especially important to Peter, because “on the heels” of denying Jesus, He comes to restore Peter by commanding him to prove his love by being obedient to fulfill His will for him…
Many times we can focus on the condemnation and shame we have, for doing something like Peter in denying Jesus.  But what we can bypass in Peter’s shame, was his struggle to know who he was after his denial.  He had to ask himself, “where did my confidence truly lie, faith in God or myself, and what I thought walking with Jesus was going to be like”?  (Romans 8:1)
No matter who we are, God takes believers through “valleys” that tests everything we could possibly be leaning on, other than Him.  It could range anywhere from our prestige, physical appearance, spouse, children, or even our ideals about life.  All of these things we don’t know we hold onto, until God brings us “face to face” with whatever it is, versus allegiance to Him… 
What is fascinating about our Lord is that He knew what Peter would do, when his idea(s) about walking with Him failed.  Yet in His great mercy, Jesus restored Peter with the opportunity to prove his love for Him by obeying what he was called to do. (Luke 22:61)  
From failures, Peter learned to live upon Jesus more, and his pride and idealism less.  So when failures/disappointments come, they don’t shackle us in shame and condemnation, but come to reveal and prune idols that were always there.  Receive grace to learn and press on obediently by His mercy, proving we do love Him as Peter did. (Philippians 4:11-13. Hebrews 4:16)
In His Love, Ld