I know I've posted about the importance of balancing things and taking breaks before, but reminders are always a good thing. Especially since it's so incredibly easy to get caught up in life that we push ourselves too hard, try to do too many things, and keep driving to be better or do more until we break down. And that's really not good.
Feeling overwhelmed by the amount of work you need to do on a story? Take a break, drink some water and take a walk, then come back to it and tackle it one page at a time.
Feeling guilty because your day job is cutting into your writing time so you're shoving your writing time into your relaxing time? Cut down the writing time for a little bit, make sure you have enough time to rest and recuperate from the day. You can always bump it back up once things die down at work.
Feeling too stressed about anything at all? If you can, try and take some time off from it--whether it's a few hours or a week--and do something that makes you happy instead. You'll feel way better when you come back to whatever was stressing you out!