For me, what works:
1. Exercise like a crazy person.
2. Sleep in decent quantity.
3. Tunnel vision.
1: This isn't always easy to do. My husband's work provides a basic gym membership (we pay the small amount extra for childcare). We also have an apartment gym. A lot of workplaces have this benefit, but a lot of people don't know about it. I know it's hard to fit workouts in if you have a job, but if it's possible, it's extremely helpful. My life has completely changed since we got this membership. You don't need a gym to work out, of course; but certain climates make it really hard during the cold of winter or height of summer.
2: I've had lifelong insomnia, and it's gotten worse every year since I graduated high school. I finally reached my breaking point a year and a half ago and got myself some help. Sleep medication has also changed my life. My doctor told me that anxiety and sleep deprivation go hand in hand. If you're anxious, you can't sleep, so you get more anxious, so you get even worse at sleeping, and so on. I finally started sleeping again, and 99% of my anxiety evaporated. I still have bad days, but it's all but gone most of the time.
3: Certain things still overwhelm me. Monday morning, after a lazy weekend, only doing the basic cleaning, I look at my apartment and wonder how I'll get it all done. I force myself to only look at one thing at a time. I make a to-do list, but then I completely forget about it unless it's time to check off a task and look up the next one. Before I know it, I'm halfway done and surprised at how quickly it went.