Yeah it definitely helps to be well rested. This kind of activity isn't well supported by a night of heavy drinking - something I personally had to conquer in order to not have not gotten rusty and lose the ability. Too hard to keep concentration on the details you have planned for yourself - you'll enter the void and stay there till you wake if you don't have proper momentum.
That might be the way to get by it - it might not. The mechanics of fear definitely have clout with whether or not you get through that phase. I likened it to killing yourself when I started - it really was that scary.
I've also experienced the same thing upon becoming lucid my dream state. I've been having trouble remembering my dreams and/ or being lucid lately so i've been researching and reading up on techniques. This might sound a little silly, but i've found through research that distracting yourself within the dream state can help you remain in the dream. For example, If you are in a lucid dream, the moment you began to feel as if your being pulled from that realm start spinning in circles or counting your fingers. By doing so you re-shift your focus from the fact that you are awake within an dream and your mind remains conscious,but the body asleep. I haven't had the chance to try this technique for myself, but i hope it helps you remain in your lucid dreams.