Not saying that the person you spoke to in the post office doesn't know their job. However, having been around for a while and sending and receiving lots of stuff to and from the US. 6 weeks for Air Mail is just not on. I sent my stuff about 3 days after you said you sent yours and you've got yours already and that only took a couple of weeks.
Air Mail has never taken 6 weeks from the US to here. 2 weeks, 2 1/2 weeks, but never 6. That's more like what you guys call surface (sea mail).
Anyway, it's Tuesday 27th and still no sign of anything. Someone, somewhere needs a good kick up the bum for it to be taking so long. One has to wonder, if it actually did go Air and not Surface by mistake. Has been known to happen.