You are studying to help others emotionally and with their unhealthy thought processes and yet are believing the lie that you are a failure. Somehow that doesn't seem healthy.

My first prayer is that just because you are having some issues with your homework that you won't allow the devil to use that to convince you that you are a failure.

My second prayer is that God will give you wisdom. Wisdom always hitches a ride with understanding. Sometimes in order for us to fully understand stuff, God allows us to walk through the fire. I pray that the Lord will give you the knowledge before He gives you the words so that when it is time for Him to use you in the mental health field, you will be as effective as He needs you to be. This failure thought has got to go. In the name of Jesus Christ I pray, Amen. I also pray that God will show you the ways that He is already using you in people's lives so that you can gain a little encouragement. Sounds like you need some. Hang in there and keep pressing on. In the name of Jesus Christ I pray, Amen.