Why art thou cast down, O my soul? and why art thou disquieted within me? hope in God: for I shall yet praise him, who is the health of my countenance, and my God. (Psalm 43:5)
God's hope is never failing. He does not abandon us in our time of need. Even though we feel alone, He's waiting there to light our way.
All throughout our lives, we will come across situations that are not joyful, are hard and test our strength and faith. Some of them we can look at and say "pfffft - I can handle this" and we do so without a second thought. We also come across those that push us to our limits, seem bleak and hopeless and our first thought is to run as far in the opposite direction as we can. God says "stay". Then there are times when He tells us that it is time to change, it is not or no longer part of His plan.
How do we know? Only through faith and prayer will our soul be able to "hear". My mother used to call it "gut instinct". You will hear people say "oh, be grateful for what you have - it could be worse." Well, when the "worse" arrives, then what?
When something threatens your spiritual, mental and physical well-being then it's time to make a change. It's time to look beyond what you have and look ahead to the future He has planned for you. You WILL know, if you listen with your soul. The power of God is amazing - trust it!