N.H.
How old is your son?
Transitioning seems to affect kids all the time, especially when they aren't old enough to express precisely what is bothering them, so they just stick to you and hope you make it go away. I've offered this advice to another mom, and it seems feasible if your son is old enough ...
Pick him up a stuffed animal, anything with a personality, but none of this high tech voice enabled stuff, and introduce the "Bedtime Buddy" to him, explain that Bedtime Buddy gets upset when he gets all cranky and clingy because he's sad and why don't they just comfort each other, telling stories and such to each other. This will help with his imagination too, and when he's tired enough and comforted by his Buddy's presence, then he should be able to fall quietly asleep. It also seems to me that Dayne just needs some time to fall back into his routine, and that you should be Tough Mama and make him see that he has no other alternative. Giving in to him is just going to make him more defiant to get his way as he tests the waters with you, the same way he tested them with grandma and grandpa.
Although, having absolutely no family within easy travelling distance, I know how you feel and you may be right about transferring some of these feelings onto him. Maybe you should adopt a mantra, like when I feel upset or frustrated, around him, I usually say over and over "It's going to be alright." and that soothes my son completely. Both the sound of your voice, and the repeated lull calms both of you enough to focus on other things.