Yea, imagine how hard it is for us to get use to that on a video game....then put yourself in a quarterback's shoes when he has 4 or 5 and sometimes 6 guys wanting to rip his head off every single play.
This of course is excellent advice...Taking the correct drop, and stepping up in the pocket at times is a must to avoid the pass rush and gain that extra second or so to throw the ball at times. You just have to trust your pass protection, and remember that getting sacked isn't the end of the world. Especially if you only take a 4 yard sack as opposed to the 11-15 yard sack I see alot of people take online. I don't think some people ever take their thumb off the down arrow when dropping back. HA!
One tip to knowing how to take the correct drop is to allow the computer to drop back for you, just as they're setting up in the pocket, you can take back control of them, however I do not do this regularly, but it does help in practice mode to get a feel of what drop you should take. Usually you can tell by your primary receiver route...if it's short, you'll probably take a 3, 5 step drop for a medium route, and if it's deep, take a 7.