I posted this on the networking FB group and people seemed to appreciate it. So, here is is again for our new students who haven't heard it from me before and again and over and over even more. :)
I always start by asking if the situation is illegal, unethical, or immoral. If it is, quit immediately. No question.
If it's a matter of difficult people or difficult work, the first three weeks are often difficult in a new job. My students and graduates have heard this many times. Get your calendar and go 3 months forward. Make a note, "If the situation is still bad, take action." Then you release some of that stress. If you start to stress about it again, remember that you have already scheduled an action date.
The situation may change. The people involved may change. Often at the end of that 3 months, there's no problem. On the other hand, if it is a problem that is not going to get better, it will probably come to a head before that three months is up, and you won't wait.
After the day I had today, this is so true. Hard not knowing what is in the future.