As menopause progresses, changing levels of hormones can stress the body physically. This, in turn, stresses the adrenal system which controls your stress response, causing symptoms such as anxiety, stress, stress palpitations, low mood, mood swings and depression.
Some women find that these symptoms can come on suddenly with no apparent reason and can be quite distressing. This is why we pay a lot of attention to supporting the adrenal system during menopause. I would suggest a good multivitamin and mineral supplement, extra magnesium such as Salus Haus liquid magnesium and a herbal stress remedy such as Passion Flower.
Eat a good diet with plenty of fresh foods and drink enough plain water every day (dehydration can make both hot flashes and stress worse). Learning to breathe deeply through the anxiety can be very helpful, and 30 minutes of relaxation a day is really important (you can get lots of good relaxation CDs through Internet).
For the hot flashes, you could try A.Vogel Menopause as this is traditionally used for hot flashes and night sweats. In this situation, getting a good night's sleep is vital; if you don't sleep well, this stresses the system further and it can end up a vicious circle!