I have herntiated discs over and over again. Having said that though, I would still LOOOOVE to deadlift again. You can't blame the exercise for your injury, it's your unpreparedness for it. Do as pumpster said-do your hypers, do some supermen, do some machine back extension if you have access and then go back to it if you feel up for it. But from the symptoms you are describing it sounds like you could have already herniated a disc(if only slightly). Whenever you sit down, you should have some lumber support. I seriously used to carry around a rolled up t-shirt to put behind me whereever I went. This makes sitting so much more comfortable it's not even funny. Otherwise, if you're anything like me, sitting for two hours would be torture.
Last, when you are symptomatic like you are now-do some Mckenzie(sp?) exercises. Basically lay totally flat and push your upper body, hips flat to the floor as high as you can get it-this is a way of manually pushing the discs back in. Hold each rep for a full 20 sec and do 5 reps or so, up to 5x daily.