The symptoms which you give are suggestive of perimenopause which we call as climecteric in our terminology.In average women the mean age of menopause is around 51 years however it is variable amongst different women. The periods being irregular and your mood swings point climecteric that is changes before menopause ( complete cessation of menses) Irregular menses should however not be of a concern but you have not mentioned about the flow pattern that is are they heavy ?
Next Steps
You can do a hormonal test that is serum
FSH(
follicular stimulating hormone ) which may give us a clue whether you are heading towards menopause. Along with it it is preferable to get a sonography of pelvis and a pap screen at this age.
Health Tips
Considering your period issues and mood changes we can start you on mood stabilizers till you achieve complete cessation of the periods and consider HRT ( hormone replacement therapy )post that but prior to start you on HRT we need to be sure of some parameters lie your blood pressure , pap screen and breast evaluation like a mammography and family history of cancers.