I agree with "myself" in that it could be a med reaction, but I would also say that it could be dissociation, the depersonalisation you suggest. I have not constantly used dissociation throughout my entire life but I do occasionally have episodes of depersonalisation with symptoms such as you describe - the fogginess, feeling of 'not really being here', feeling like you're living in a dream - and they have been triggered by high anxiety, which sometimes is the result of a specific event but othertimes comes out of nowhere, with anxiety having been high for at least a few weeks. When I have had this, the maximum time it lasted was over a week, and sometimes it lasts only a couple of days. You do say though that you still have quite high anxiety, and from what I remember when I have been through similar episodes, I was emotionless, and of course, dissociation is an escape from feeling things, either physically or emotionally. So I would say that the fact that you are still feeling things emotionally would suggest more a medication side-effect... how long have you been on the antidepressants for?