Your boyfriend may be stressed out, but that doesn't give him permission to take his stress out on you! You need to put your foot down with him and tell him that while you are sorry for all his troubles, he may not continue taking them out on you. Then tell him that if he isn't able to control his behavior with you, then he needs to get help.
Then, you need to put your money where your mouth is and the next time he starts to go off on you, you tell him straight out, 'You stop talking to me the way you are right now. ' If he refuses to straighten out, then you leave the room or the house. Keep in mind that their are no victims, only volunteers, and if you stay for a verbal beating, then you have only yourself to blame.
Plus, your tolerating his behavior sends out the message to him that he may mistreat you. So, make sure that your actions and words line up. That when you say no, you mean no, and you follow through by not allowing him to dump on you.
I hope that his problems straighten out soon. My thoughts and prayers are with you both.