You're someone who clearly holds the ability to look for the best in people. This is a truly beautiful ability that not all people have. I wish there were more people like you in this world. You also obviously hold the ability to sense the need for speeding up your own evolution, hence why you employed this guy. This is another unique ability, to search for the best in yourself so as to move forward with greater ease.
Wondering if a different perspective will help in the way you see the situation with that 'life coach'. Would you say he coached you in coming to understand the nature of a narcissist? Did he coach you to better sense and trust those 'red flag' feelings (intuition/gut instinct)? Did he coach you in some way to be an even stronger empath than what you already were, feeling more deeply? While an expensive lesson, I imagine you still learned from him.
I can relate to having been burned by people who had their own agenda while appearing to care. In hindsight, I can say I learned a lot from such people. Some of those lessons were either incredibly angering, leading me to beat myself up at times, and even deeply depressing. If there's one outstanding thing I learned from each of those people it was about learning to trust my feelings/my instinct. I suppose you could say while you're looking for the best in people, it pays to wonder why you're feeling the red flags. Sounds like that life coach needs greater lessons himself. If you're a believer in karma, perhaps they're on their way.
Personally, I was fortunate enough to meet a truly beautiful life coach a number of years back. Actually, he was one who chose to become more of a spiritual coach. One of the things he said that made a difference to me is something I'll share with you - On the path to becoming who you truly are, there will be things that come up that may lead you off track. Forgive yourself and get back on that path to becoming the best version of yourself. There will always be people who throw mud and sh*t at you along the way, in the process, and you gotta practice washing that stuff off so you can keep on going to find the best in yourself. Easier said than done at times :)
If it's of any help, a brilliant book (in my opinion) is 'Becoming Supernatural', by Dr Joe Dispenza. It addresses how we tick holistically - mentally, physically and naturally. It may perhaps help shed some light on why you're feeling so exhausted, lacking in the energy you're so desperate to feel.