Is the schooling allowance monthly?
The 18k will get you a comfortable villa or flat but rents are rising. The utility allowance should pay your electric, water and your internet. The car allowance is sufficient also in my opinion. Take what you have left and decide for yourself if you can save money from the remainder of your pay.
I don't mind Doha but then I get to leave fairly often. I preferred living in China as far as culture and daily life go. The school my children attend here is better than the international school in China.
Your mileage will vary depending on what your expectations are.