Depression 

Much of depression is situational.  Depression in this case is a loss.  Something you once had is now gone and you probably cannot get it back. A job, a death, a divorce, a dream? Is the loss something that you can touch?   Did it really happen or are you fearful it may  happen? Once you have separated the reality from the imagined, you can begin to grieve the loss.  A close friend, relative or professional counselor can help you through this.   You can rely on Jesus to be with you and grieving with you.  One might ask "why did Jesus let this happen?"   There is no easy answer for this other than we need to trust that He will help us through any of life's disrupting events.