What else than stress can be the reason for no menstruations in 3 months, sudden appearance of a lot of pimples, great hair loss and increased apetite?

First get preg test: Many reasons, it could be your thyroid gland, you can check it with simple blood work, also can be a condition called poly cystic ovarian syndrome (pcos) is easy to get diagnosed from your history, labs and ultrasound . Also make sure you don't have any eating disorders such as bulimia, also extensive exercise can leads to delayed periods. Very important to make sure you are not pregnant by pt.