Disappointments are a part of life; we've all experienced them, and we'll probably experience them as long as we live. Job said we are like travelers in a desert seeking water, only to find the stream has dried up: "They are distressed, because they had been confident; they arrive there, only to be disappointed" (Job 6:20).
But is God to blame for every disappointment? No, of course not. Often we set goals for ourselves that aren't realistic (or even wise) -- and yet when we can't reach them, we're disappointed (or even angry or bitter). Or sometimes people disappoint us, because they don't live up to our hopes and expectations. Circumstances change also, forcing us to change our plans and abandon our hopes. And sometimes we are our own worst enemies (as the saying goes), because we refuse to do what's necessary to reach our goals.
Let me ask you a question: What had you planned to do with your life once you retired? Were you hoping simply to have a good time, living only for yourself and spending your days in mindless entertainment or self-centered indulgence? But God has something better for you -- not just enjoying life (although that has its place), but also using your talents and experience to help others.
Seek God's will for your life, and be thankful for whatever He sends your way. Begin by committing your whole life to Jesus Christ -- including your job and your future. Then see each day as an opportunity to serve Him -- even through your job.