Possibly, the tag fell off of your bag at origin or during a connection?
If the latter, sometimes the bag may have been wrongly handed to a different airline - they assume it came from.. - Who knows?
If it occurred in Africa - Good Luck; especially if it contained any valuables!
Of course, you had your Name & Address on and in the bag didn't you?
Lastly, if you carry such expensive belongings; it would be advisable to have travel insurance to cover the value of your goods!
Sorry to say; if it's still missing after five weeks, then it's probably gone for good.