Hi,
This sounds about right for a Senior level western educated Engineer with a good CV.

It is worth checking out if they cover school fees (assuming you have kids) as these can be very expensive. Also find out about medical insurance, medical repatriation flights (are they covered) and shipping of personal possessions

As a rough guide, I live in a 2 bedroom apartment, modern, clean yet basic, that is about 2500 USD per month without utility bills.

Check your contract too, see what is included and what is not mentioned (i.e. excluded).

On the bright side, life in Qatar can be great, it is what you make of it :-)
Hope that helps

Tom