used to keep a mood diary. it helped me cuz my moods came with "cause and affect". that may not be your case, idk. what i found was if something happened and a bad mood followed i'd write it down..like reflect back to what occured before my mood changed. journaling helped me too. my T suggested i reread what i wrote about my day then underline words that described how i felt. it really helped cause i could see what triggered the change in mood. also found that certain times of the day had a correlation with my mood.
and yeah i'd have your doc check your estrogen levels. when my mother went thru menopause it was no laughing matter... she had a difficult time of it.