If your tracking information says Pre-Shipment, please allow a day for USPS to scan it into their systems. Most of the time when it says pre-shipment USPS has already picked it up from us and will scan it in as soon as they start to move it.
If it says Not Found, that means the tracking number hasn't hit USPS's system yet, and we probably just created it before you got your shipping confirmation email.
Either way please allow a day for their systems to update and the packages to move.
Holiday seasons will cause more of these issues than normal.