"Always remember that your present situation is not your final destination. The best is yet to come." - Unknown
If your life isn't where you want it to be, change it. It's what successful people have done for thousands of years. You may currently be struggling and frustrated with your life but it's not going to stay like this forever, that is, unless you don't do anything to change it.
The best time of your life may still be ahead of you but it won't just magically show up, you have to create it. It's in your power to create whatever future you want for your life. Even if your best days are truly behind you, you can still have plenty of great days ahead of you if you decide to make it so.
Instead of letting circumstances control and defeat you, use them to push you into action so that you can change your present situation. Bad times aren't going to last forever but if you want more great times ahead of you instead of just good times, it's time to start doing things that will make that a reality… it's time to work toward your ideal destination.