Yes, You have to level the floor. The floor level guy must be a sifu to acheive a good level floori.
Good Luck on this, My advise is better use a good Sifu if you can find one, skilled guys are rare.
And also regarding the laminated flooring, Get the expensive grade. A few $$$ more will be worth it as the floor is a non replaceble item especially when tou build a built-in wardrobe over it. (You cant very well change the fllor after that without diamantling the wardrobe.)