LCD monitor making me feel dizzy

[RiverRider]

I've been playing online poker for years on my Dell Inspiron 9300 with a 17" 1920x1200 monitor. I decided a week ago to buy 2x LCD 24" 245BW from Samsung and plug both of them on my laptop as side-by-side dual monitor to multitable. The thing is that when I play for 2-3hours I start feeling dizzy and almost get headaches... I never felt like that before when playing on my laptop even if I played for 8hours straight.

I guess its because those two screens are too big since im about 2feets from them, but on the other side im getting addicted to all that free space for pokertables and would like to keep using them... Is it because they are brighter than my laptop screen? Is it like travel sickness and I will eventually get used to it?

Any help would be appreciated!