You need to find an outlet to relax. Go for a walk, Drink tea, speak to a friend about your stress don't bottle it up - that's when you'll yell at people.
Hello dear, you are under stress because you are trying to do your best, and that is commendable. It is very important that you use google and read, read, read about how to handle your stress. Here are some techniques found on Wikepedia. You are in my thoughts and prayers.
Getting a hobby
Spending time in nature
Clinically validated alternative treatments
Planning and decision making
Listening to certain types of relaxing music, particularly:
New Age music
Sleep Music 
Spending quality time with pets