Hi kreel11.
While the actual GMAT is generally pretty similar to the official practice tests, every GMAT, whether real or mock is a little different. Also, some questions that are easy for one person can be hard for another. So, depending on what questions you get, your GMAT could seem easier or harder than normal for you.
So, there are a few things you can do.
One is to expect that any given GMAT you take could seem a little easier than normal or harder than normal. Having that expectation, you're less likely to be thrown off by an unexpected level of difficulty.
Another is to be sure to prepare in a way such that you become ready to answer a wide variety of questions, even one that don't quite resemble questions you've seen before. The GMAT tests our ability to come up with a path to an answer on the fly. You can develop that skill by answering a wide variety of practice questions, including third-party questions, to become accustomed to coming up with a way to deal with a question that's a bit different from any you have seen before.
Finally, strategic guessing could be a key tool as well. If you see a question you don't feel prepared to answer, then ditching early could be the move. Of course, if it's among the first 5 questions, doing so might not be a great option, but in that case, you can still do just do your best to answer it and cut your losses if you're not making progress. It's better to move on and get other questions correct than to overstay and mess up your timing.