Oh God.
I always think my pens are going to run out. On exam mornings I start out with 3 pens in my pocket and then I think "what if all 3 run out?" so I'll grab a fourth, and then I think "what if all four ran out?" so I grab a fifth... it keeps going on until I have about 20 pens and then I realise it is ridiculous and settle for 3 pens.
I'm also worried there will be traffic on the way to school making me late so on exam mornings I usually end up at school ridiculously early.
But my worst fear ever is running out of time in the exam! I can NEVER finish exams on time. I was super worried in my decision maths because in the mock I end up getting an E because I missed out like two whole questions (there is about 8 on the paper and the grade boundaries in decision are super high) - in the actual exam I JUST finished on time - I kept speed writing after they'd told us to put our pens down and just finished as he came around to collect it in.