Why dont have people with a severe thrombocytopenia any sleeping dissorders?

Hello,
Today i´ve learned that thrombocytes transport serotonin from the gut to the cells. I know that serotonin is very important for sleep because it will be metabolised to melatonin. Now when you have a thrombocytopenia you should have less serotonin because you have less thromboytes which can transport them to the cells. How comes that patients which a severe thrombocytopenia dont have sleeping dissorders or depressions? (90% of the serotonin is made in the gut) I mean, i have 10.000/μl and i sleep like a bear (when i want 12 hours a day). I know that serotonin cant cross the blood/brain barrier but i´ve read something about the vagus nerve which send the signals from the gut serotonin to the brain.