Meg, the Blenheim bitch I had in the 1990s, was very nervous when I had her. A couple of times, when we went out to a Sunday BBQ with friends, she was too stressed to eat her supper when she came home and woke up in the night screaming (definitely screaming, not a gentle whimper!) - I assumed she was experiencing the stomach cramps that we get when very hungry. I quickly realised what was happening and made sure she ate something in the evening, even if it was just some scrambled egg, and the screaming stopped (she also gradually got more confident) - but yes, even simple gastric problems can produce blood-curdling screams! So worth checking this out with your vet.

Kate, Oliver and Aled