Mood swings can be cause by a lot of things. It can be hormonal, it could be brain chemical, it could be depression, it could be bipolar, it could be borderline personality disorder, it could be PTSD....you really need to talk to a professional and tell them ALL of your symptoms, even those that seem insignificant, to get a good diagnosis. And if the diagnosis seems off to you, seek a second opinion.

Good luck and welcome.
Seesaw