First-time wetsuit, leaking around the neck

I took advantage of the current 60%-off coupon on xterra wetsuits and got myself a Vortex 3 for under $200. It seemed to fit pretty well on dry land, tight, but not too tight, no problem zipping it up, no baggy bits. However, today when I wore it in the water for the first time, I immediately got a load of water down the back of my neck, and when I tried to adjust it further, another load down my front. This is the first time I've ever worn a wetsuit, and I hoping I just didn't have it pulled up sufficiently around the neck. I'm going to try it again tomorrow, but in the meantime, if anybody has any advice, I'm eager to hear it. Also, after my suit was thoroughly wetted inside (top half), I found it very difficult to adjust, so I ended up just taking it off and hanging it up to dry. Is it even possible to put on a wet wetsuit, i.e., should I have taken it off and then tried to put it on again?