Mental Block

Why is it that when you want to write - either because you need to due to deadlines or you just really want to get some words on paper - your mind decides not to make sense of anything?  That is the phrase I am in at the moment.  I really do want to write and I also really need to write but I just can't motivate myself to start.  My mind is finding other things to distract it - things that are complete time-wasters.  So I'm not getting anything done and feeling guilty about that but I just can't get my mind to slow down enough that I can work out what is wrong.  Is it just me that gets these mental blocks?  I refuse to admit I have writer's block as I hate that term, I don't believe in it and it isn't just applying to my writing now - it is a block against anything remotely productive and I have no idea how to get my head out of this funk - any ideas would be very welcome.