What is wrong with me? Is it all mental? Or something more?

Guys! I am having the following things going on, and would love any help I can get. I am a twenty-one year old girl. I have lived a normal life. I eat healthy and don't smoke or drink. I am a college student. I have always had fatigue problems, and never felt that 'sex drive' that other people do. My periods are whack. But lately I have started to feel really depressed, anxiety, awful fatigue, difficulty with attention, chronic headaches. I also have had weird sleep patterns, my memory and social skills are shot. My emotions are gone Everything that once was fun and exciting is frightening. I am so scared to move on. Is there hope? I miss life! Can antidepressants help? Anyone have any advice? When I read things on sites, people scare me away from them. I have come to find that most all medicines seem to never even phase me. HELP, please!

Period problems could be caused by a number of things such as stress,hormonal imbalance or a thyroid gland which is not working properly.
Fatigue could be brought on also by stress,depression or thyroid.This is what I can think of at this moment.