Since you are taking anti-depressants, I assume you are being treated by a professional. If you haven’t shared this information with your provider, you are doing yourself a great disservice. A professional only has what you tell them to go on.
This habit could have developed out of loneliness as a child. It could indicate that you have an especially imaginative mind but don’t know what to do with it. Or it could be that there is an organic problem. Or it could be something else. Without investigating it, your mental health provider can’t help you figure it out.
I wish you well.