I have read several questions on the usage of "I myself", but didn't find anything about whether it's OK to insert things between them. Would it sounds right?
I had doubts myself on whether I did this question right. or I have doubted it myself whether I did this question right.
(Or maybe there are some other problems in these sentences I gave or anything else I said, I'm not great at grammar, especially tenses... but you get the idea. Thanks.)