Gladiator have dificulty holding agroo from ppl on early levels, there is not much you can do until you get shieldOat, then it becomes better.
For now try to mix vit/str gear like 3vit an 2 str on accesories an that can help a bit, another thing you can do is mark the mobs so the dps focus on the mob you attacking, so far I think thats about it until you become PLD.
also flash as much as you can, like most of the time.
good luck