Why does God allow suffering?

This has been a questing I have been struggling with for quite some time now. Why does He allow things like depression? Its been over 4 years now that I have been struggling with depression. Over the past two years It seemed to get worse and am now on some meds to try and help me. It seems like there is more suffering right now then Joy.

Last week at bible study we were told as homework to write down a question you want to ask God then go to the bible to find the answer... I chose to ask why he allows suffering, since this is something I have been struggling with daily. This is what I found out.

Romans 5:3-4 " We can rejoice too, when we run into problems and trials, for we know that they help us develop endurance, And endurance develops strength of character and character strengthens our confident hope of salvation"

1 peter 4:1-2 " So then, since Christ suffered physical pain, you must arm yourselves with the same attitude he had, and be ready to suffer, too. For if you have suffered physically for Christ, you have finished with sin. You won’t spend the rest of your lives chasing your own desires, but you will be anxious to do the will of God."

2 corinthians 1:4-5  "He comforts us in all our troubles so that we can comfort others. When they are troubled, we will be able to give them the same comfort God has given us. 5 For the more we suffer for Christ, the more God will shower us with his comfort through Christ."

Job 36:8-10  If they are bound in chains and caught up in a web of trouble, he shows them the reason. He shows them their sins of pride. He gets their attention and commands that they turn from evil.

I dont think that all suffering is from God, some of it is from our choices we make, the consequences of our actions. God gave us free will and lets us learn from our mistakes and hopes we will come to him. When I was looking up the verses I noticed that alot of the times it speaks of people suffering and why we suffer is because we suffer for christ, and it builds us up and makes us stronger. It may not be pleasant, but In the end we will rejoice from our suffering. hmm.... One of the verses says that Christ comforts and helps us in times of troubles so that when someone else is going though the same thing we can be the same comfort that christ was. The more we suffer in Him, the more God will comfort us. This is a hard thing for me to grasp because I am tired of suffering, I hate this depression, I want my life to be "normal" again, but we have to hold on to the promise God has for us  "For I know the plans I have for you; Declares the LORD, plans not to harm you, plans for good and not for evil, plans to give you a hope and a future."(Jeremiah 29:11)