It could be pre-menopause or even menopause -- even at 44. Many women who have had children early in life (like in your teens) have early menopause as well.
I agree with keeping track of your cycle. Is it regular and on time? Also write down what you're eating. Diet can have a big impact on our moods.
I also agree about being very detailed with your doctor. If s/he isn't responsive, find a new doctor!