So treatment options are the pill or mirena coil - which I would really recommend
However, if you don't want to go that route, then the other main treatment is a medium dose of antidepressants from after ovulation to when your period starts again. Anti-depressants are often life changing for this, and the benefit from taking them compared to not, is huge. They are perfectly safe if you have worries ask those specific questions, and ask for the most detailed information from your GP.
PMDD is caused by an abnormal brain response to normal hormone fluctuations, particularly in the luteal phase, when progesterone levels fall sharply. In PMDD, the brain’s sensitivity to these hormonal shifts is greater than in people without PMDD, which is why the pill or Mirena can help by stabilising hormones (the Mirena often works better).
It’s also why SSRIs are the most effective non-hormonal treatment, because serotonin levels and receptor sensitivity are biologically affected more than environmentally or due to a traumatic event etc contributing to rage, anxiety, low mood, and suicidal thoughts. SSRIs work directly on this serotonin dysregulation.
Therapy can however be extremely useful to compliment antidepressants, especially for coping strategies, emotional regulation, and relationship impact.
Why don't you want to go on antidepressants? Do you not think they are safe, or is it the stigma about it or or doubts they’ll work? It’s important to talk that through with your GP because the evidence for SSRIs in PMDD is very strong, and leaving PMDD untreated carries real risks; relationship breakdown, job difficulties, and suicidal thoughts. The risk of it continuing over you not treating it because you don't want to take antidepressants, is much greater than the risk of anything from the antidepressants.
Depending on your age, I'd ask your GP about starting a low dose of vaginal oestrogen as well to help with the low libido, energy etc. Then get a good vitamin D and vitamin B6 supplement, to help with the emotional side and cognitive/brain fog issues as well. Take it every day, but definitely in the week leading up to and during your period.
You can self-referral to local IAPT for therapy or or via your GP. If symptoms are severe, which they sound like they are, ask your GP to refer you to psychiatry or perinatal mental health services as they are very equipped with PMDD. Perinatal services will treat you even if you don’t want to get pregnant, as many perinatal mental health teams also manage PMDD and hormonal mood disorders outside of pregnancy.
I've attached some links which should be useful on treatments you could have. The first is about getting a diagnosis.
https://www.mind.org.uk/information-support/types-of-mental-health-problems/premenstrual-dysphoric-disorder-pmdd/getting-a-pmdd-diagnosis/https://www.mind.org.uk/information-support/types-of-mental-health-problems/premenstrual-dysphoric-disorder-pmdd/treatment-for-pmdd/