For what it's worth, Dog9, I felt that way too. Detachment from different aspects of ourselves (our thoughts, memories, body, etc.) makes us see through all the normalizations that everyday life is construed around. Most or all things lose sense, once the normalized framework of how they are brought into correlation by human societies falls down, due to such detachment. It is a difficult and lonely place to find oneself, but it is not impossible to come back. Well, I never came completely back to where I was before, as I still see through most of the normalizations, but then again, I do not feel like a complete alien all the time any more. I wish to say that there is nothing wrong with you. You are detached from certain aspects of yourself, and there has to be a root cause to that, but in such a state of detachment as is yours, it will probably take some time to wrap your mind around what is causing you such distress.
For the time being, try to lead your life around some routine, if possible. What was suprising to me, when I felt that way, was the understanding that most people actually do not see what is going on with me. I was fortunate not to have to go to work every day, as I worked as a freelancer. CBT helped with certain explanations, such as that even though you feel alien and therefore think you seem alien to others, they do not necessarily see any of that...anyway, it took me some time to reach the root cause of my state, and ofc every experience is different, but my point is: take all the help you can get, even though it may not seem helpful at first, such as therapy. And be sure that, even though the experience is overwhelming, and seemingly places you out of everything that is human, it most likely comes from a certain place within you, where it is possible that some conflicting or painful experiences reside.
Wish you all the best,