Toddler shaking and moaning.

So my July 2017 Toddler still feeds to sleep, I am trying to wean her but that’s a different story. She sleeps In a crib attached to our bed. What concerns me isn’t new, but I am curious. At times she wakes up in night, moaning, startled, shaking Like shivering, . I know I also wake up shivering at times when I wake up from deep slumber. But it takes me a min to calm her down mostly. Hugging her and rocking her or just giving her water or boobs calms her down and she goes back to sleep. I don’t know if it’s something to be concerned about, like is this a seiZure or something? Any momma has noticed this or heard of this?

Thanks in advance I am really worried.