Hi Panda
Depending on your periods you may well be per-menopausal. If your cycle length is changing each month and varies by more than a week then officially you are (!) - that is the medical definition, combined with symptoms. Typical symptoms would be flushes and sweats though sometimes these don't appear immediately.
Anti-depressants should NOT be prescribed as the first line of treatment for menopausal symptoms so not sure if your doc knew of your changing cycle or even asked? Mood changes may well appear before flushes etc, especially if these are cyclical? Great advice from CLKD to keep a diary so you can see if there is any pattern?
Blood tests are not needed to diagnose menopause unless you are under 40 and sometime betwee 40 and 45, and you're having irregular periods. This could be an indication to start HRT due to early or premature menopause.
If you feel HRT would be beneficial then you should ask for it, but depends on some of the factors I mentioned. Also depending on your age then the contraceptive pill QLAIRA is designed for peri-menopause because it contains estradiol (bio-identical oestrogen) the same as in HRT, but suppresses the cycle - not sure of its effect on mood but it will certainly even out fluctuations from your natural cycle, and mitigate any associated mood changes. There are also some gentle HRT low dose pills like Femoston which some women find helpful in perimenopause.
Hurdity x