When we go astray from Christ and ignore the work of the Holy Spirit there is still great hope for us. Consider what is happening in the Gospel According to St. Luke:
"And the Lord said, 'Simon, Simon! Indeed Satan has asked for you, that he may sift you as wheat. But I have prayed for you, that your faith should not fail; and when you have returned to Me, strengthen your brethren'" (Luke 22:31-32).
What is going on here?
First, even though Peter, the exemplar of faith (Matthew 16:18), lived part of his life in an ongoing, experiential contemplation of Christ, his fear overtook him such that he was capable of betraying Jesus three times. Thus, he understands the difficulties you face in prayer.
Second, Jesus prayed for Peter! It's awe-inspiring and humbling to think that the ever-living God will join you in your own prayer. Despite knowing that Peter would betray Him - and regardless of the sins God knows you're going to commit - He makes whole what is broken in you. In Peter's case, Jesus tells him simply to get back to work when this period of sin and betrayal comes to an end.
The lesson here is to keep trying and keep asking. God knows your weaknesses better than you do; and He still loves you. Implore St. Peter for his help, He will strengthen you along the way.