another thing which happens to quite a few people is that they get excited witht the vibrations, get excited about the fact that they are about to enter a lucid dream.

i remember when iv tried wilding in the evening when i first go to bed (extremely hard to do) and after half an hour of laying there, i went numb and felt a tingly sensation. it felt like the speed of blood pumping round my body hard increased by about ten times, to the point where it was pumping so fast that it made me vibrate.

i got really excited and snapped out of it. and was really anoyed with myself.
it is important to try and stay calm during 'the wierd stuff'.
and the mnore you experience this, the more normal you will find it and the easier it will be for you to stay calm.