Yeah, those are definitely OCD-like symptoms. The even/odd thing is very common, though I've never heard of anyone associating it with letters. Usually it's just people have to do something an even number of times (usually it's even, not odd). With the letters, though, it's quite clever.

The blue thing - that's very interesting. So you would picture in your mind everything you saw covered in blue? It must have been hard in a car, with everything racing by.

Not wanting to make mistakes is also a big thing. I have something where if I have to scratch something out, I have to make a scratch mark in the margin so that I have an even number of scratch marks on the page. I also have to do that if I write the letters st on a page, because I associate that with saints, and I think I have to write st an even number of times for some reason...I'm not even a religious person, lol. I try to keep that "st" one to a mininum, though, since it shows up in so many words.

Anyway, it doesn't sound like you're imagining things...definitely some OCD-sounding symptoms there. Hope that at least gives you some comfort.