Why? It's common. Haven't we all reacted more strongly than expected due to other stressors in our lives? I had a complete meltdown last week. I'm going through a divorce and something a family member said sent me over the edge. What they said was hurtful but on a normal day would have simply stung.
She is supposed to be sweet and happy and grateful. Married to the love of her life. Nothing but sunshine and roses right?
They were children when they married and barely knew each other. Of course it's a huge adjustment. The difference is, a non fundie is allowed to feel whatever feelings they may have. They are not. They must keep sweet. When she experienced a miscarriage not only was she mourning a lost child like any human would but, it was also an outlet for all her unhappiness.