Here's your problem with calling yourself an "amateur archaeologist":
First, when you detect, you are digging into the ground and retrieving things with no consideration of everything around it. An Archaeologist finds an area, then completely grids it off. They then very carefully dig up the site, making careful notes, drawings, and taking pictures of each item found, how it is situated, depth, angles, etc. They also number and itemize each item as they find it. Do any of you do that? NO. Calling yourself an amateur archaeologist will nothing but insult a trained archaeologist.
If you want to call yourself an amateur archaeologist, I recommend heading out to a college, and having a sit down with a REAL Archaeologist. If you can convince them that your interest is more in preserving history than just digging up things that make your metal detector go BEEP, then they may let you participate (with your metal detector) in archaeological projects, but you won't dig your targets. When you get a signal, you will pinpoint it, then mark the spot with a little flag. An Archaeologist or Archaeology Student will then come over an carefully dig up what you detected.
If you take the time to learn about archaeology, preservation methods, site preservation, excavation, etc, then you may legitimately call yourself an "amateur archaeologist". Otherwise, you will just get embarrassed if you try describing yourself as such to a real Archaeologist.
Mike