During chanting / meditation I sank into a state defined by very short breaths/ barely breathing, and I could feel my whole body pulsating. Is that normal?
The response you’ve described, while not the “average” experience of people chanting, is not pathological, either. It seems to me that you are going into a highly internalized state of awareness, and as a result, some prana is beginning to flow in ways that you don’t normally experience, which makes the body pulsate (or at least, it may feel that way — perhaps someone watching you wouldn’t be able to observe any movement).
If that overall experience is pleasant, or at least neutral, it’s fine. Let it come when it will, and let it go when it will. If it is unpleasant in any way, then probably best to stop chanting (or whatever else you’re doing that seems to be bringing on this state) for a time.
And in any case, call strongly on God and the great masters to guide your practice. Think of it as a blessing, and offer it back to God with gratitude.
In divine friendship,