Regarding unideal clients: "If making you happy costs me MY happiness, I can't afford you." There needs to be a mutual fit and satisfaction of interests. If all you have is one side taking advantage, that's not a good or profitable business relationship.
God has so much more in store for you than what He's asking you to let go of. Bigger and better blessings that are unimaginable to you are coming your way if you'd just listen to Him. Trust in The Lord. Our God is an Awesome God! Perfect picture of trust.