Yes, it does sound like your timing was "off" on test day. Your quant score dropped more than your verbal relative to your last practice test. How early would you say you finished quant? Do you think you were rushing on a lot of questions because you were worried about possibly running out of time? Rushing often increases our rate of careless mistakes.
And, yes, guessing on the last four in a row on verbal can bring your score down 2 or 3 scaled score points (around 7 to 10 percentile points, depending upon various factors), so that alone could have been what caused you to drop from 38 to 35. (And I'm guessing that you probably rushed on at least a question or two before that, right? Most people will speed up first, trying to catch up, and then finally realize they just have to guess at the end. If you did that, that would also have contributed to a score drop.)
So, timing problems often take 4 to 6 weeks to completely correct and solidify. Here's an article on timing:
http://www.beatthegmat.com/mba/2009/12/ ... managementI think you would also benefit from a timing exercise: learning about how long one minute is without looking at a watch or stopwatch. If you don't have one already, buy yourself a stopwatch with lap timing capability. When you go to do a set of problems, start the stopwatch but turn it over so you can't see the time. Every time you think one minute has gone by, push the lap button. When you're done, see how good you were - and whether you tend to over or underestimate. Get yourself to the point where you're within 15 seconds either way on a regular basis (that is, you can generally predict between 45 sec and 1min 15 sec). Note: at the same time that you are using the stopwatch to time this "1-minute" thing, also use the OG Stopwatch (in your student center) to track the total time spent on each question.
Now, how do you use that when doing problems? If you're not on track by one minute*, make an educated guess** and move on. (The general idea is that if you're not on track by the halfway mark, you're unlikely to figure out what's holding you back AND have time to do the whole problem in the 1 min you have left.)
* For SC, 1min is well beyond the half-way mark (we're supposed to average about 1m15s here), but you can almost always eliminate at least some choices on SC in that timeframe. Once you've got that "I'm around the 1min mark and I'm struggling" feeling, go through any remaining choices ONCE more. Pick one. Move on.
** This also requires you to know HOW to make an educated guess depending upon the type of problem and the content being tested. So that's something else to add to your study: how to make educated guesses on different kinds of problems.
Let us know if you need help with anything else!