I tried a WILD last night, and during the relaxation phase I became really short of breath. Is this common?

I think this is the closest I've come to WILDing. I mean, I wan't completely relaxed, but I was definitely getting there.

P.S. A tip for relaxation which worked quite well for me:

Think about your favourite book. It has to be a book that you know really well. For me, it was "The Catcher In The Rye." Now, what I done was imagine myself making it into a film. I'd picture the opening credits, the music, and I'd think about the first chapter in the book, and transfer it into visuals. And now and again I'd get really caught up in this and forget what my intentions were. It almost worked. Just a little suggestion.