I really can't comment for how stressful the ATC environment is, but I can certainly say this. Xavius ATCC has been cited by many real-life controllers as being a most realistic simulation of the radar control environment from the stress point of view. I used to 'play' it.. Play is not really the word. There's not a lot of 'fun' to be had. It's extremely demanding, physically and mentally and after a 30 minute session on ATCC I would usually come away feeling the same way as I did after having sat a 3 hour exam. It's extremely challenging and hard to keep your mind moving fast enough to pick up everything it needs to.
Having said that, it's extremely rewarding at the end to see that you've handled it fine and everyone has landed/departed safely.
Where am I going with this? I'd say, grab yourself a copy and give it a decent go for a decent length of time. It should be a good way of introducing you to the environment and some of the demands towerguy spoke of. Then you can find out whether or not it's for you. It's free too, so why not?
Go to
www.xavius.com if you're interested.