Often people put on a mask, to please other people or not to show their weakness. Sometimes you do this unconsciously and this way you can realize:

You are a completely different person at work/office/school then you are at home. This is because home is your comfort zone and you might feel at home and different at work.

When you feel asked out by others, you pretend to be busy and rejected but feel lonely when the time comes. This might show how you want to socialize and yet might have anxiety issues.

When someone asks you whether you are fine, you say yes I am and feel hurt inside might also use humor as a defense mechanism to gel in or to seem that you are ok.
Even though you have a great external facade you feel a void inside. You feel difficult to compose yourself in situations yet you don't show it outside. It takes a great amount of time for you to become emotionally available.

You just need the courage to show who you are it's okay to feel sad or moody. The only way to control your emotions is to know them. Let them free so that they come in your way. You have to get out of this sad cycle and be who you are.