Hello, Mood swings and anger around your period may be due to premenstrual syndrome. This causes physical changes (physical symptoms such as bloating, weight gain, tiredness, etc) and also mood changes. If your thyroid level is where your doctor wants it to be, it is unlikely that Levothyroxine is causing you the mood changes. The fact that the mood changes are related to the menstrual cycle is another indicator that the most likely cause is premenstrual syndrome. I hope this answers your query. I remain at your disposal in case further medical assistance is needed. Regards, Dr. Antoneta Zotaj General and Family Physician