Can you do me a favor and check if your tracking number gives some info on the USPS site?
I didn't go through every single one I've sent, but went through several. It appears yours is the only one that hasn't started updating. I just spoke with my local postmaster and he said chances are it wasn't scanned when they picked it up. Since none of the other international packages started updating until the past day or so, I would say none of them were scanned for whatever reason. He also said that it should start updating once it is scanned at another facility.
In the end, if it is lost or you don't receive it for whatever reason, I'll refund or resend. I've sent literally hundreds of packages and only had one lost, so just give it some time and I would say it will find you. You're covered regardless though.