First, that sounds truly awful. You have my sincere sympathies. I found this to be a good read. Maybe you already read it.
Researchers, physicians and psychologists fall on various sides of the debate over premenstrual dysphoric disorder.
www.apa.org
I think it's also terrible if anyone told you or made you feel that it was all in your head.
Regarding psychaitry, I think it's best to go with a practical approach. If it works and brings relief, that's what matters. The diagnosis and class of perscribed medication doesn't.
To put things in perspective, depression is sometimes treated with anti-psychotics even though the patient is not at all psychotic. Even the label, anti-psychotic, is not a good descriptor of what the medication does. I saw in the article that anti-depressants are perscribed for PMDD. That doesn't mean that PMDD is depression. I saw that it is classified as an unspecified depression, that's just a label, a placeholder. And I also saw that some don't like the PMDD diagnosis because they claim it encourages a sexist stereotype about women on their cycle.
So there are a lot of issues here. And even, arguably, the mechanisms of the oldest known mental illness, schizophrenia, is not well understood.