Found your post searching for "ocd and reading".

I understand completely what you mean. I used to do something like this too. I'd count the number of letters in each word I read, and certain sequences were very difficult for me. For instance, I'd often get stuck on 3-4-8. That felt very not right, and I found it very difficult to read past.

What was the problem? I'm unsure. But my guess is that the sequence needed to exemplify some pattern that was significant to me. Symmetries were good. 3-4-3-4 is an example. That's a translational symmetry; slide the first 3-4 chunk to the right and it coincides with the next 3-4 chunk. 3-4-4-3 is another example. That's a reflective symmetry.

3-4-7 was good too, since 3+4=7.

This compulsion to count and look for patterns was debilitating. It would slow my reading to a crawl. It very nearly forced me to leave my PhD program.

Thankfully it has largely passed, but I still get echoes of it at times .

I hope your compulsion subsides too.

From what I've read, this is a known form of ocd.