Just get ya a harness and force yourself to do it. Eventually you will get over it. Something like 9 of 10 Americans are actually afraid of heights. So don't feel bad.
I'm not afraid of heights, I'm not even afraid of falling...it's the abrupt stop that scares me. I only use my climbers and haven't been in my ladder in three years. It all depends on the ladder stand itself, if you have one that's got a wrap-a-round shooting rail and a good foot platform it's no problem. All of the ladders on the land I hunt, except mine, are just an open seat and platform. I stopped hunting them for fear I was going to fall, even wearing my harness.