I have the same letter-counting thing ever since i can remember, but only a few months ago I happened to find out that this is actually unusual...
I can count letters both in sentences i read and hear. I do it very quickly, and can tell a person how many letters were in a sentence he said the moment he finishes saying it. and i alphabetize as well. and can type/ say a sentence from end to beginning very fast.
but I don't do it all the time, so I'm not sure what it all means...
I was never diagnosed with OCD, but when I was in grade-school I had different kinds of nervous ticks, like nodding my head, which I eventually grew out of. now, I guess, this is the only thing I have left...
a funny thing- I found out I can also count bits I hear faster than other people (like if you knock with your fingers on a table quickly like 'ta-ta-ta-ta') I can count them one by one, and i found out other people can't
so...I'm really happy I found this forum!!!
please write if you a have similar "issues" :-)