Everything changes. Our environments are constantly changing, our bodies are constantly changing, our moods are constantly changing, your thoughts are constantly changing.
The only constant in life is the spirit of our own awareness witnessing our lives, a spirit that seems unchanged from childhood to old age. When we reach outside ourselves for anything lasting, we suffer because everything outside is impermanent. We find fullness and freedom from suffering only when we reach within and abide in the spirit of bearing witness. From here, the flow of change delights rather than terrifies us.
Change is like a tsunami coming right at you. You have a choice. You can cross your arms and hold your ground, refusing to adapt. If so, the tsunami will crash into you, breaking every bone in your body but still ultimately taking you wherever it wants. Or you can choose to embrace the change, to ride the wave, to surf the tsunami.