Stress is one of the biggest causes of hormonal imbalance. Stress can be emotional stress like relationships and work stress, or physical stress like pain, injury or lack of sleep which is a major cause of stress, and finally it can be caused by dietary stress from a processed food diet or eating foods which are causing an inflammatory reaction in your body like gluten.
Stress leads to an increased production of cortisol which will lead to a depletion of progesterone, it can also create an inflammatory response which will block the progesterone receptors, so even if you have enough progesterone the high cortisol will stop it from working. High cortisol will affect the messages coming from your hypothalamus and pituitary gland in the brain which are the master controllers of the hormones.