An individual environmental footprint is not strictly measurable in a physical scientific sense, unless you live a life which is completely detached from others. The normal human existence is so deeply entwined with the lives of others that you cannot measure the precise impact of your own actions.
There are so many different ways in which we (speaking as a middle aged white western European here) are destroying the planet.
If you want to know about the impact of humanity, averaged over all people, then the Earth Overshoot Day is a good guide. This year in fell on day 235, meaning that the average per person resource use is 50% too much.
The Paris Agreement sets out a frame work for trying to decide how much each nation should do to address the climate emergency angle of sustainability. This deals with the tricky question of how the economic cost of not destroying the ecosystems that sustain life should be shared out.
The bottom line is that just about everybody needs to make significant change. Good luck, I hope those two references are useful.
PS: there are many calculators which can give you an idea of where your individual choices can make an impact. The World Wildlife Fund has some good suggestions on their Measure Your Impact page, and they recommend a footprint calculator provided by the Global Footprint Network.