Is this normal?

I know a lot of these posts are light hearted and a bit on the flippant side, but this time I'm serious... is it normal to read through the race info then be gripped by complete panic and spend half an hour in tears?

Quick explanation: I'm slow, and wearing any amount of fake fur will make me slower. My pace is closer to 'fast walk' than 'slow run', and I am expecting to be towards the back of the field. I've been getting on pretty well with my training walk/jogs despite all the whinging, and know that in theory I can cover the distance comfortably, just not at real speed. I got to the part which tells you that for the purposes of clearing the roads, a vehicle will be following the pack at a set pace of 17 minutes per mile, and anyone falling behind this vehicle will be deemed to be out of the race. What if this is me? What if, for whatever reason, I become too slow during the course of the race and get kicked off the course? Or what if I really struggle with the fur and start to look really uncomfortable and get advised to quit by medical staff? What if the weather is freakishly hot? Or what if the fur gets weighed down by torrential rain? What if excessive sweating brings on a bizarre fake fur allergy? (OK, sorry, the mental image that conjures up is not nice, I know...) All these thoughts and more have been racing through my brain. For the first time this evening it crossed my mind that I might not finish the race, and that thought is just unbearable.

I'm tired, so this is all 'me me me' at the moment. I have no idea if Taz is feeling remotely like this, and I'm not going to ring her up at 11 something at night just to vent my spleen about it. But this is definitely the lowest I've felt so far. Plus it just dawned on me that we haven't given serious thought to accommodation, and with 50,000 people taking part that's more than a bit important. Pass the Gaviscon...