[ElsatheDepressionSlayer]

You should definitely be honest with your doctor. He needs to know the whole picture so he can help you as well as possible. I would suggest telling him your symptoms (including the self harm) first, then telling him your and your counselor's theories. That way he can see the information without any preconceptions and probably diagnose/treat you more accurately. He needs to know that you aren't taking your antidepressant, because that will be an important factor in how he goes about treating you.

Finally, as far as I know, it's rare for someone to get hospitalized for self harm alone. Unless you are self harming to a point where your life is in danger, they most likely won't hospitalize you. Psych wards are generally really full, so they choose to admit people who are in the most danger (like being a suicide risk, very extreme self harm, etc.).