You absolutely should not press on. If you're missing everything in the OG, that means you're not ready for those problems. In any case, just doing a bunch of OG problems is not an effective way to improve your score. You need instruction, repetition, and review.
First, if you are missing *all* the problems, you should probably start with the fundamentals. One good source for that is our Foundations of GMAT Math book. You can also go to free online resources such as Khan Academy.
If you have the fundamentals down, you should be getting at least some of the OG problems right. Some problems are really just testing one or two rules. If you are getting those but struggling when the problems get harder, it's a matter of working on your organization. Write down what the question is asking for (e.g. Female employees/Total employees * 100 = ). Try to estimate and eliminate unreasonable answers. Go back through problems you've done and identify the traps and difficult spots. To consistently get moderate to difficult GMAT problems right, you need to have a strong sense of structure. You need to learn to see the difference between the information the question is providing and the information is asking for, and you need to practice making a plan to get from one point to the other. You're not going to get any of that from just doing a bunch of problems.
So again, start with instruction, probably at the foundational level. Then start looking at real GMAT problems from a perspective of organization and strategy. Again, a book or two can be helpful if you don't have access to a teacher.
Good luck!