Sometimes WILD just doesnt work. I'd say WILD depends 85% on your body and 15% on your awareness. If your body decides to enter sleep while you are aware you have WILD onset. Otherwise you just lay there until your body is ready.

Numbness is not a sign of WILD, it may result from lack of movement and poor blood circulation. Cold may cause shivering that also may be mistaken for a sign of WILD.

What you should try is set your alarm to 4-5 hours into sleep (experiment with the number of hours), so you break your REM cycle and wake up in the middle of a dream. Then quickly turn off the alarm, relax and let yourself drift asleep while being a little bit aware. Focus on a single thread of thought (but not what you have to do tomorrow or anything like that). You may also focus on a single image (a familiar image or the last image of a faded dream).
This WILD attempt is very short. If you dont get a LD within 15 minutes just let go and try some other day. WIth this method your chances are way better than just trying to WILD at some random time during the night and even if you fail you lose ~15 minutes from your night.