You can invert the shank and use it either up or down. I agree witht he others that you need to raise the front and the proper way to do this is to move it up on the shank.
If the shank is pointed down and there is not another higher hole to use, then turn the shank around so it points up. You can usually find a hole that will let you get the trailer just about level.
I am assuming you are using a weight distributing hitch that has an adjustable shank. If you are simply using a drawbar with a ball on the end, and it sounds like that may be the case, then you need to purchase a shank and a WD hitch to use on that trailer.
Barney