Hey there,
You are not insane. Often times, those who have been abused want to feel little again, because little feels safe. And that's totally okay. It doesn't make you insane to want to act like a child sometimes, and it can be very therapeutic.Sometimes we have to deal with our inner child, the one who was hurt for so long, and acting little can help that.
I know people who act little sometimes, I do it too. They suck their thumbs, or curl up with a blanket, cuddle with a stuff animal. Sometimes it's easier to talk about it, if you think like a child. Some therapist even encourage it. If you haven't talked to anyone about it, you might want to talk to a counselor or a therapist, they can help you. There is play therapy and experimental therapy that works, and that allows you to be little sometimes, just give it a try.
If you need anything, feel free to
pm me.