This goes against prevailing SV ideology, but man, it's just a job. Don't ruin your health or wellbeing for a company that would fire you in a heartbeat if it made economic or political sense.

Commit to your family, your friends, your hobbies, and charity. Don't commit so hard to a job, because ultimately it's a business transaction. Companies _will_ take advantage of your good will if you let them. Don't give them that opportunity. You owe them nothing beyond what you agreed to in your employment contract.