Mal-
I know what you mean (not what you personally experience of course) about not being able to stop intrusive and disturbing thoughts from entering consciousness and being distracted by them. Its exhausting the vigilence it takes to be bombarded with unwanted stimuli to the psyche and senses and then have to constantly recognize and dismiss these thoughts. Sometimes we get too depleted of mental energy to keep on top of them all and find ourself lost in some psychotic thought process or autistic shut down and its hard for others to appreciated the energy it takes to come back to ourselves.
I hope you are able to to keep renewing the energy you need - I know for me its almost impossible to get any stored up.