One thing I notice in the game translation field is the difference in how senior and junior translators react to adversity, whether that's in the form of poorly organized source files, urgent deadlines, or client mandates that nobody agrees with. So here's some basic pointers.

1) Unusable/disorganized source files: This happens. I've gotten entire spreadsheets of dialogue with no listing of who's speaking. If you can't work on a file as-is, decline and send it back ASAP. Put the ball in the client's court to clean it up. It's not for you to solve.

2) Next-day deadlines: These are generally bad-faith in nature and not actually urgent. You can refuse them. Either the client will negotiate a more reasonable deadline, or they'll find someone else who meeds their exploitative needs better and you'll have dodged a bullet.

3) Client mandates: Sometimes you make a case for a certain choice and back it up with citations and evidence, and the client just responds, "Do it this other way instead." The resolution here is: You tried. Now it's out of your hands, so do it their way.

If you're a freelancer just starting out, learn to recite this three-word mantra that will soothe your soul and help you sleep better at night when you repeat it enough:

"Not my problem."

Save your mental energy for things that you actually have the power to solve.