That's quite an extreme reaction to holding a firearm, even if a loaded one.
Nah. The gravity of holding something that can easily kill, especially by accident, can really put someone on edge before they acclimate to it.
I felt about that way my first time behind a steering wheel (and my first time on the freeway), and also on the odd occasion I've handled firearms. In my head I knew they're only tools, but my gut felt like it would jump from my hands and attack someone if I wasn't supremely attentive.
Didn't feel that way with airsoft guns or a bow, though – maybe it's because it's harder to injure someone by accident with those?