I Have Been Having Frequent Dizzy Spells Which Require Me

I have been having frequent dizzy spells which require me to lay in bed with my eyes closed. There is no spinning. I have been checked out by a ENT Doctor and have had a CAT Scan and a MRI and they found "nothing to be alarmed by", These spells last anywhere from 4 to 8 hours at a time. I just had another one yesterday, woke up at 8 AM and it lasted until 3 PM. These spells can come on at any time, sometime I get them in the morning and feel okay in the afternoon and the other way around. I also sometimes have double vision plus I have something called occipial neurogial but I don't believe they are connected to the dizziness.