Depends on many factors such as how she behaves once she is under the table, and how fast she 'recovers' when she emerges, etc. It may be just a temporary adjustment period, maybe a general lack of confidence due to previous environment, or it may be something genetic, or even medical -- hard to say without actually seeing your dog. So you be the judge. If it greatly concerns you and/or you're unsure how to interpret the details, I'd suggest a consult with a professional for a thorough analysis.
In the meantime make sure you provide her with some kind of mutually acceptable place where she feels safe. Perhaps a plastic clamshell crate with the door removed.
Keep in mind too, that standing and 'towering over' a pup can be sort of intimidating to them, even though it seems rather innocuous to you. Some gradual desensitizing and counter-conditioning using food rewards might help.