Undead Hunter Pets WOW?

I just started playing WOW and im at lvl 14. I searched for some answers on this but cant find any so Im asking here. So I am playing the undead hunter and I got a spider "pet". I have all the pet abilities and when i try to tame a different pet i get a message saying that i already have the maximum. Dose that mean I can only get one pet the whole game? How would I change if I could?