I found the TEAS V exam to be relatively easy. That, likely, is because I got decent grades in the prerequisite courses. I also took a pre-test, found out my weak areas, worked on those for a week or two, and took another pre-test and did VERY well on that. I ended up getting something like an 87 or an 88 on the TEAS and if you were to look at the percentage of scores from where I was at, I was the 99th percentile. My school requires a minimum passing score of 67 and as you can tell, I very easily surpassed that.
The main thing is that the schools set their own standard for what they consider "passing" while the TEAS folks have shown that generally speaking, a score of 62 on the TEAS V (or 67 on the TEAS IV) is highly predictive of being able to pass Nursing School.
Don't stress too much, just make sure you know the basic material, take a pre-test about a month out, then study your weak areas, then take another pre-test about a week out, and as long as you've got a decent score, you'll do just fine on the "real thing." Those ATI pre-tests really are pretty close to the genuine article and the score you'll get from those pre-tests will be in the ball-park of what you'll get on the exam day.
In my case, like the person above me said, I found the TEAS V to be relatively straight forward and decently plain English. I didn't find it all that stressful, but it wasn't a cakewalk either. You just have to know the basics and take enough time to actually read the question that you're asked to answer. Their questions aren't designed to trick you. There will be only one right answer and that answer should be VERY obvious if you know the material and actually read the question, read the answers, and re-read the question.
The biggest thing for you is to simply not panic. You do that and your brain will lock up so badly that you'll need a swift boot to the head to unlock it... or some time to process it all later.