HELP! My plumeria is wilting?

I recently just bought a plumeria plant that already sprouted leaves. It's roughly 2 feet tall. It is actually starting to wilt, the leaves on the bottom are drooping over. I am not to sure about watering it but i water only when the soil is dry...I'd say about every 3 days if not more. The trunk of the plumeria seems normal (like hard but squeezable). I put it out in the sun everyday for six hours if not more, it's not on concrete or anything. Please help, this is my second plumeria plant and i seem to be plumeria-challenged. THANKS