How long will it take to get a international package from the u.s to australia?

[pingumatt]

I bought some socks of Ebay on the 4th and they were shipped off on the 5th it was First Class Package Intl Service they shipped them off from America and i live in Australia its now the 18th and they havnt arrived iv called the local post offices but they dont have it how long would it take to come here including business days and would it come by mail or a van will drop it off? or am i just over reacting it feels like its not going to come 😞