Hi Jason,
Whilst I haven’t yet fainted due to meditation, there’s something in your post that sounds similar to my recent experience (
link). In brief, over the last few months I’ve noticed ‘pulses’ and ‘shifts’ in my body, rather like the weightless feeling one gets when going fast over a bridge in a car. Occasionally these ‘moments’ are strong enough that I feel I may faint but this hasn’t yet happened. In the post I’ve provided a link to, Dream Walker notes that “shifting from 2nd 3rd and 4th vipassana jhanas was just like you describe for me”, which made good sense.
The other thing is that reflecting on not-self/dharma does cause a noticeable shift in consciousness, into a wider and more inclusive experience, that can feel a little dreamlike (at first) but mainly because of the initial shift into a more alive and clear space. Wonder if any of this helps?
Best wishes,
Nick