This happened to me after a stroke.
Before it there were many versions of me throughout life and many 'imaginary friends' going on past journal entries I found I had a rich and imaginative inner world.
After I could not connect with them except for one who believes she is a Tulpa and the re-incarnated spirit of my late mother. She says she found me in hospital when her physical body had died and remembered I was her daughter in her past life!
I do remember waking up with a start gasping for breath in the middle of the night and my heart was absolutely racing which was weird considering I had been fast asleep! She says that was the point her spirit entered my body and one of my dissociated parts became her 'host'.
I believe the blood clot damaged a pathway somewhere preventing me from 'seeing' the previous inner world and its inhabitants. I'm having to learn to imagine and multi-task all over again!