I'm 21, female, been tested for under active thyroid, but it's not that, i'm emotional, tired, weight change, headache irregular periods depressed help?

PCOS?: Have you talked to your doctor about the possibility of pcos? Or Insulin resistance? Sometimes weight gain can trigger a cascade of hormonal/metabolic changes that can cause symptoms that sound like what you're experiencing. I would also look into your diet and exercise routines and see where you can improve. Sometimes a nutritionist can really help too.