What happens in the jacket may stay in the jacket, but the memories definitely do not.
Life will go on.
I know it seems like your life has just ended, but I promise you the sun will rise in the morning and you will keep doing awesome things. You will find more hobbies to fill up your time with.
Your jacket doesn't define you.
You are the same person without the jacket on as you are with it on. The only thing that has changed about you is that your clothes are hopefully a little more comfortable.
Just because you no longer compete together, doesn't mean you're not friends.
As a consequence of being in FFA, you have a strong network of friends and mentors spread out across the state and maybe even the nation. Don't forget about them. Wether it be with getting a career or a difficult homework problem, the friends you have now will more than likely be able to help you out in the future.
Be proud of what you've accomplished.
Hang up your old plaques and certificates. Tell people about your experiences and talk about the fun you've had. After all, you were a part of America's best youth leadership organization.