Yes, the stress is too much! Stress will kill you, it's keeping you from sleeping now. Stress will rob you of your happiness. Your life is worth more than that!! If you don't believe me, ask the people in your life that love you.
For those who say companies want Walmart managers, you are right, but only if you get out first and then go to another company. Hiring companies are full of naive hiring managers and dumb HR people who literally think if someone is laid off, they are in some way damaged goods. Don't wait to be laid off by Walmart. You know you are great at what you do! Start working your plan, get out there and make contacts for a new job. Let them know you bring your A-game and are ready to go! You will get a better job and get out on YOUR terms. Life will suddenly get better once you are out.
This is how Walmart will lose their talent. Talent doesn't have to stick around and take crap, talent walks away. Believe in yourself and take back control of your life.