You are not your platform. Here are some things you might consider digging into.

Your hard earned skills are not wasted. The time and energy we put into building high quality software is valuable on many level. We are practicing specific skills related to specific technology, but we are also practicing so much more than that. Hopefully you’ve been consistently upping your game and applying design patterns, best practices, unit testing, and other core skills that are timeless and platform independent.
Nothing is forever. We live in an age where the bleeding edge of technology is moving fast. For me, there are several development ecosystems that I find particularly appealing outside of Flash/Flex. If I was to sit down and start learning today, I’d be elated. The resources are enormous.
Python - http://learnpythonthehardway.org
Python is an awesome language. I personally think it is aesthetically pleasing and have spent considerable time with it. The Django framework is mature and robust. It provides a solid foundation for building responsive web applications. It is truly a joy to work with.You get a strong sense of craftsmanship from Pythonistas.
Ruby - http://ruby.learncodethehardway.org/
Ruby is a great language and has a vibrant community behind it. You can build high quality apps, and the Rails framework is extremely mature at version 3 and is the backbone of many popular internet applications.
Node.js -http://www.nodebeginner.org/
Node is an event driven server side JavaScript environment. It is relatively new to the scene, but man has it caused an explosion. It has a vibrant and growing community and provides a lot of interesting opportunities.
The above technologies share something in common. These are not specifically front end technologies. They all sit firmly in the mid-tier. Each will work just as well with DHTML++ (ok ok HTML5) as they will with Flash/Flex front ends. They are all fun to work with as a programmer, and provide the challenges that leverage your existing core skills to make nice things that people can use to get work done. They are all also completely open platforms.
What is missing from that list is front-end technology, specifically HTML and JavaScript. I’m actually of the opinion that HTML and JavaScript have come a long way and provide some interesting opportunities fro development that doesn’t suck. I see apps like http://trello.com and I step back and say “hmmm, this is really interesting” - performant, usable, enterprise class web applications using html/js/css is a distinct possibility. Not there right now, sure, but it is approaching. Check this out: http://brunch.io/ - serious potential here.
Beyond specific technology, what should you be doing? I’m constantly trying to increase my “soft” skills. The Pragmatic Programmer, The Passionate Programmer, Apprenticeship Patterns (get this today. right now.), Clean Code, The Clean Coder, Working Effectively With Legacy Code, Introduction to Algorithms, Visualize This, Head First Design Patterns, Refactoring, Patterns of Enterprise Application Architecture, Visual Complexity, Business Models, The Lean Startup, 4 Steps to the Epiphany, Pragmatic Thinking and Learning, The 4 Hour Work Week, Rules of Play, Game Design a Book of Lenses, Programming in Scala, A Pattern Language, CODE, …
This is a good time to be a nerd. These are areas of study that I have personally found enjoyable. Look around, and you should find something you enjoy too.