I find having eyes partly closed helps. Opened enough so that I can focus on something in the distant. that way I don't feel like I've lost the connection with the emptiness
I've never bothered tying to syncronise my breating or movement to with anyone else, it allows me to slow down at my own pace.
The energy being low at the end might just that you are trying too hard and you ned to let go and breathe at a pace that is right for you.
Alex
