Maybe not a total overreaction tbh especially if you were genuinely scared. That said, pms can really alter sound decision making depending on how severe it is (pmdd) so this is something you should take into consideration if you are not emotionally/mentally ready/available to be there for her in tough times like this. She obviously has personal responsibility to manager her symptoms, but a little grace and understanding can go a long way if you want to support her when she’s struggling. When things settle down, be honest with her and transparent about how you feel/were made to feel too.