A simplistic way to determine the environmental "footprint" of your lifestyle and decisions is to use a 'footprint calculator'. WWF has a good one that provides you an indication of the number of planets we would need if everyone made the same decisions you have made, in regards to transportation, food choices, waste generated, energy usage, air travel and size of your house.
Have a go!
WWF footprint calculator
See what impact your lifestyle is having and maybe provide you with some inspirations for ways to change and you reduce your impact.