People are confusing. Your friend who changed on you - totally confusing lol. But God isn't. I thought I knew God pretty well a year ago, but I still am learning so much through His word each day. Just like Paul said in Philippians 3:10, I want to
know Christ. And Paul knew God pretty well, obviously. Not know about Him but to know Him on a personal level. His words in the bible are many, but things and life just start making sense as you continue in it. And as you continue in it, you'll find answers and enlightenment to stuff you've wondered about. Don't let how this guy has changed and the outcome of your hurt from it confuse your thinking that it's God who caused it. Sometimes God puts people on my heart and I pray for them and find the same peace you found while you were praying for your friend. But then it goes away and I just have to leave it in God's hands. I know it's a pain sometimes to not have an answer right away (especially if you have little patience like me :/) but it's just something we have to wait on. I pray that you continue to have peace through this whole situation and hopefully find some answer soon.