It could be attributed to the DXM, but it could also be attributed to many other things, environmental toxins being one... your ordinary eating patterns, whether you choose to eat healthy food without artificial sweeteners or any other crap in it... If you are into "fringe truth" subjects like 2012 or anything like that, it could simply be the state of reality itself is shifting... for example, how would you know what to "say" if time were dissolving into singularity? Who knows. Personally, I have only done DXM twice. I have been noticing the same stuff you have, and long before I tried DXM. Really, if time were dissolving into a singularity like many sources point to, than that would mean we would be "becoming" our thoughts more than simply thinking them.
Put it this way. Feelings are here and now. Thoughts refer to the past, or future, in some way or another. We think to relate ourselves in the past to something probable in the future. We worry about work tomorrow, we think about whether or not something is going to do something... Again, feeling is here and now, and thought is past and future. So if we were slowly evolving towards no time, that would mean we are in the middle of a transition away from the mind, and more becoming and feeling the mind infinitely in the here and now, as here, and now, is all we have ever really had. If we will eventually transcend time, that means we will have to become past, present and future as one... If that were the case, what would the point of thought be? Thought simply would "be" as one... in the here and now, as feeling.
So that's mainly what I think it is all about. It could be the DXM as the catalyst, it could be our higher selves, it could be nothing... but whatever it is, just like talking, it's like piecing together each other's puzzle to reach a mutual point of understanding... and my point is, where does the entire universe come to a "mutual understanding" of itself? Transcending time, and thought and becoming one in all it's being. So with that said, if you are having trouble say, "getting into the flow of life" or whatever... try not relying on thought as much. Go with your gut, and what your heart tells you is right. Our heart knows much more, instantly, than we can logically "piece together" in our heads.
So if you have a question for yourself, don't ask your mind. Clear your mind and ask your heart and you should get a gut feeling one way or another.
If any of this interests you, check out
http://www.mayanmajix.com/TZOLKIN/DT/DT.html
Otherwise, I would just recommend treating your body right whenever you can, and listen to the deeper voice inside you as I too have noticed my "logical" side has been scrambled into infinity more and more every day. We can rationalize anything, and that's the point... to become everything.

:D