Why is nothing ever simple!

I have lost my theory test certificate. Why?! The other day when I needed to do my physics coursework I couldn't find my notes and now that I need something else they appear and the thing that I really need disappears! I am so stressed out this week and this is only making it a million times worse. If I don't find this I can't do my test and that's £100 wasted. I'm in London tomorrow so I have to find it NOW or I never will before my test. :'(