Think I reached SP?

Earlier I tried to WILD during a nap and had no success. However, most of my body felt very relaxed, and my left arm went completely numb (my hand was almost impossible to move, bar a few fingers). It felt like when you sit on a limb for ages and it goes weird and immovable, only I wasn't applying any pressure to it, so surely it was SP?

Also, how would I go about getting my entire body to get like that?

For me, my entire body enters SP at the same time. It might have been SP or your arm may have fallen asleep.

You might want to look at the link in my signature. This might help you know if it was SP or not.