1) Understand the new reality
Your brain thrives on steady stability, but now your world is changing around you and you're struggling to grasp your place in it. You need to make sense of what is going on. Luckily, you have some options.
Talk it over - Keeping your anxiety inside won't help you make progress on the change you're forced to deal with. But simply talking with someone can help you piece together your fears and help get your bearings. In most forms of therapy talking through your problems is also working towards solutions.
Writing it out - Getting your thoughts out of your head and on to paper can assist with making your thoughts and feelings more tangible. Writing can allow your to put your concerns into words, that you can now share with other people. The practice of journaling can be therapeutic and beneficial to combating stress.
Draw a picture - Before you tell me that you're no artist, believe me that you are still capable of sketching enough to make your thoughts more concrete and coherent. Dan Roam's The Back of the Napkin shows how easy (and fun) it can be to unlock your inner child and draw solutions to your problems.
2) Distinguish to difference between what you can and can't control
Now that you've figured out the new lay of the land, where do you go next? Before you start planning your next move, consider first where your efforts could be best spent.
Steven Covey introduced a concept as the circle of influence and the circle of concern. The inner circle represents the things that you can actually influence. Around it is located the circle of concern that contains all the things which you worry about, but can't really influence. To be effective, you should focus on those things in the circle of influence and yet the other things go.
3) Take action where you can
So you've got an understanding of what's going on and you've assessed the area you can truly influence, now you're ready to take action!
It's best if you start small. Smaller actions are less intimidating and less likely to be avoided. A small win is a great way to get the motivation you need to keep going.
Once you have your potential actions, find a simple way to keep track of them, such as a to-do list or a kanban. Keep track of the things you've accomplished and the results you've achieved.
Now you've come a long way from an unsuspecting "change victim" to proactively working your way through a change you didn't even know about. Congratulations, you're taking charge of life instead of reacting to it!
Also check out
Overcoming an Overwhelming Amount of Change
How to Know You're Going in the Right Direction