As you are 40 years of age and having these symptoms,so the chances of premenopause are more.The normal age range for the occurrence of menopause is somewhere between the age of 45 and 55. Symptoms of premenopause are irritability and mood swings,hot flashes,night sweating,irregular periods,decreased blood loss during periods,dry vagina,breast heaviness and tenderness and joint and muscle pain.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.