There is nothing wrong in being sad. It is completely okay. You have every right to feel like a total mess and nobody can question you. Do not ever bottle your feelings just because you are afraid of people. You may feel sadness is not leaving you but remember this feeling is temporary.
Masks too hurt at times because they conceal the real you and give you a fake identity. To heal, you need to let your pain out. Cry, scream, express yourself. Do whatever you can but do not sulk. Acknowledge that you are hurt but remember that better things are coming. Every cloud has a silver lining and after every difficulty comes relief.