How to get rid of this feeling

My whole life I’ve always been such a happy person despite having a really bad childhood I’ve always looked at the positive in life but as of the last 2 years I’ve been feeling ever sad and I cry all the time and I never find a reason to why. When I’m alone i cry my heart out and horrible thoughts in my head. But no one know I’m suffering like this because to everyone around me I’m always laughing and cracking jokes but, I just feel like I can’t take it anymore I don’t want to feel like this everyday! And I not in any medication to be feeling this way , my life is great I have a very supportive family friends I just don’t know what’s wrong !