It's not uncommon. I get shutdowns in different degrees over information or emotional overdose. Thankfully significant shutdowns are rare for me, but I get smaller ones more frequently.
I don't think I ever had a meltdown. I had tantrums as a kid, and from what I've heard about meltdowns they are easy to tell from tantrums. Apparently meltdown means an actual lack of control where even if removed from the situation, they can't just snap out of it. Tantrums apparently are over as soon as the kid is removed from whatever situation that made them tantrum. I had some tantrums and always calmed down the moment I wasn't forced to do what I was made to do. A Although my reaction was genuine, I had control over it, it was all about not wanting to do some specific things. (Skiing in one case, not wanting to wait in the cart on another occasion).