Indeed. Delayed bags are a routine of air travel (and from the experiences of my co-travelers, it seems to happen more often if you have experienced it once!) and we just learn to cope with it. My experience is that:

0) Don't pack anything irreplaceable in your checked luggage. In fact don't pack it anywhere - leave it at home. For clothing & daily stuff, I leave 2-3 days of change in hand baggage so I don't panic.
1) File the missing bag report (get WorldTracer number), confirm I will send receipts of necessary expenses due to delayed/lost bag to the airline. If they get you a prepaid card (BA does?) the better.
2) Live on. If there's something you need to replace with reasonable expense, buy it and keep the receipts.
3) Wait. Nothing will help, calling, emails, etc. WorldTracer is really a simple system where people enter their lost bags and unclaimed bags are entered within and matched by the system. Expect nothing more. Eventually it will arrive or be lost!
4) Send receipts to airline and claim compensation. No need to be dramatic - flight #, date, PNR, lost bag tag, list of contents, receipts.

If you have travel insurance, you can claim with them too. Once you get used to it, lost bags are nothing more than a minor issue in travels.

Safe travels!