What blood have they done and told you that they are normal?
If they have told you it is not perimenopause based on a normal follicular stimulating hormone (FSH) but no corresponding oestrogen level then they could be missing the problem.
Normal menopause is primary ovarian failure. In this case, ovaries start to fail with age resulting in lower oestrogen levels, your pituitary gland responds to this info in a feedback cycle and releases higher amounts of FSH in an attempt to stimulate the ovaries, hence raised FSH being seen as a marker of perimenopause/ menopause.
However
Secondary ovarian failure also exists, and is frequently overlooked. So in this case, ovaries are healthy, but there is a problem with the pituitary, so the pituitary doesn't release enough FSH, therefore resulting in failure of the ovaries and low oestrogen, and this low oestrogen causes all the same symptoms and misery.
So,
Primary ovarian failure = high FSH, low oestrogen
Secondary ovarian failure = low/normal FSH, low oestrogen.
If the GP hasn't tested, and won't take you seriously they there are online blood testing services that work with finger prick testing and will do a comprehensive hormone profile. Do it on day 3 of your cycle of possible.
By FSH 9.6iu/l with a oestrogen level of 54pmol/l when i was finally started on HRT at 42 after years of suffering. I was at rock bottom then. Since then I've had 2 years of endocrinology investigations, blood tests, urine tests, salivary test (cortisol) and MRI and I'm still none the wiser. But at least I'm on HRT. I'm on a really high dose of both oestrogen and testosterone and feel a million times better.