The user's own profile on the left sidebar is a little confusing; since the main goal is to create a "note to myself" area a good solution could be to rename it with this name, use a custom icon and background color.
But at this point the "Short text notes" area should not be present inside. So with the current UI maybe it is better to call it just "Myself" with a different background style, and inside have the two tabs "Short notes" and "Messages to myself".