When the USPS tracking information says Pre-Shipment it could mean a few different things.
Pre-Shipment can mean either the shipper has printed a shipping label and the tracking number has been created and it's getting ready to be dropped off at USPS or picked up by USPS.
Or Pre-Shipment could also mean that the package was dropped off at the USPS location or Picked up by the USPS and it's getting ready to be sorted and shipped out.