You have repressed anger about whatever is causing you lots of stress that you aren't addressing. You try to put it off but your body needs a way to let it out so that is why you're snapping at your friends.

The solution of how to deal with your stress better is really hard. Maybe look into stress management techniques or relaxation ones.

When people get stressed they often turn to short-term solutions that have long-term consequences. Eating a lot of junk food may make you feel better in the short-term, but after your blood sugar levels crash you feel even more stressed out.

Trying to avoid turning to counterproductive habits is good, but if you do some, don't rip into yourself too much. Someone who is trying a diet and eats one donut may get angry at himself, feel defeated and eat many more. It's impossible to avoid all bad habits during times of stress, just try to limit them.

Not saying you do these, just see if you're making other changes that make you feel worse. Look into stress management and relaxation techniques, odds are you should find at least one that appeals to you.