Yes. It's exhausting. I'm several years past post-grad, have had a succession of one-year contracts, doing work I love and believe in and I genuinely believe has a lasting value, but the lack of any kind of security sucks. I'm rapidly approaching a wall where by I have to either go for tenure track/something more managerial/teaching or leave for something hopefully more lucrative in the private sector.
Sadly continuing with my present (rewarding, interesting) work is not an option even though after I leave, the work will still exist and will still have to be done by someone. But the academic system, such that it is, is a conveyor belt, and you gotta move on or get off.
And I got lucky too. My postgrad experience was short, went relatively well, and I'm well paid by academic standards now. I'm constantly surprised I made it out ok given the amount of stress it generated. I know many people who had much more miserable experiences in postgrad.