When describing people, some of the terms most often used are outgoing or shy, introverted or extroverted; and that is large because people usually fall into one of those categories. However, choosing to be alone, and feeling as though you need to be for your own sake, are two very different things.
When an individual is stressed, very often they don’t want to be in social situations because they fear that it could add to their stress levels. However, while it might seem like a good solution, withdrawing into yourself can cause others to isolate you, which can have further long-term effects aside from just a little temporary social anxiety. It is also important to note that the more your isolate, the harder it will be for you to seek the help you might need.