Not so tough to pass the exam. It's good u already have got ur medical exam in ur country and passed successfully. No worries over here. The major threats normally are Aids and Hepititus. An initial stage TB can also be treated by the govt over here.

Expenses depend upon ur life style. Qatar is not very expensive, Oil is very cheap, Food is a bit expensive. House Rents are very high upto the sky. QR. 7500/month two bed room flat (furnished).