Nothing prevents you from looking for another job while you are employed.
Nothing.
And, you don't screw yourself for something someone else has done wrong by leaving before you have another source of income.
if you are getting ready to graduate, perhaps you should start interning for whatever it is you are studying for.
Crappy things happen all the time at work, how important they are to you is related to
how much you care.
and how badly it will directly affect you.
Right now many people don't even have a job (not a guilt trip) Play it safe, it's a tough market out there.
If you are certain you do not want to stay, start looking and interviewing, believe me, even doing that will ease your mind.
It's fairly easy to keep a job, you do not have to let them know what you are thinking, I'm fairly certain that they don't care.
just work and go home..but if you want to leave, you decide that and start looking.
the worst thing you can do is pay for someone elses screw up by getting yourself fired.
Then you will just be pissed off *and* out of work..(you maybe right, but right doesn't pay the bills)
Take it easy and let it chill out before you make decisions. Making hasty ones almost always screws you.