Oh yea it's a very common thing especially when trying WILD etc.

Quick tips off the top of my head (I'll try to include more in the 2nd part!):

• Focus on your breathing and don't even try to move. Moving can actually make it worse if I recall correctly.
• I'm not quite sure if this would work (I just came up with it) but if you are thinking something like "Don't think about [insert something horrible here]..." ad infinitum when in paralysis you could try twisting it into a "Don't think about [insert something less horrible like flowers here]..".

I can see a dozen scenarios in which case the latter would still backfire :D Just focus on breathing and thus calm yourself down.