I know it seems a little counterintuitive to talk about how people should react before talking about what they're reacting to, but here's our new page on getting help with your PMDD.
If someone reacts in a cruel or intolerant way to your PMDD it's not a reflection of you or PMDD, it's a reflection of them. Start the process of reaching out over with someone else.
As you get help and as you talk with more people about your PMDD it will get easier to tell people about.
I know it's hard, but be brave. Getting help is the only way forward. We believe in you and you can do this!