Why?

I feel I have been plunged into a very deep valley from a mountaintop experience. I came back from my further studies hoping to contribute in my work. But why God am I going through this time when no one appreciates my hard work and day in and day out, I feel that I am using my sweat and blood to do my work. I really cannot take it anymore and many times I wonder why I am here. Why am I going through this terrible time and more is expected of me.I need a release from this, I feel like if I have a hole that I can be inside for as long as I want to. Is this a form of escape? So why,
why God am I going through this??
I sense that I have fallen from a high mountaintop and each day is by God's grace. I want to be released from this as soon as possible.
God, please help me. It is only by your grace that I can survive each day. I really don't want to go mad.