You know, maybe I'm weird, but I've always enjoyed the sort of moments the OP mentions. It's fun to act little, and important to be an adult sometimes, but I find the strangeness when they come together to actually be it's own special sort of delight. It's hard to describe, but it's like, rather than having those two viewpoints coming together as a moment to freak out, think of it as a moment when your whole self sort of comes together. Like "yes, here I am, an adult lying around in a (probably wet) diaper! That's me, and it feels great!" I've often had this sort of thing happen when I'm doing an adult activity, like if I'm at home all diapered and I get a work email, and in my head I'm like "oh, I'm negotiating this contract in a diaper! The other side will never know. :laugh:"
So, my suggestion is, like others have said, to wear diapers if you want to and don't wear if you aren't enjoying it. But if you are enjoying wearing while also feeling that sort of "omg, what's happening?" type of absurdist feeling, try to think of it instead of different parts of you all coming together in something special instead of a moment to freak out.