Lakersfreak,
Firstly, I'd choose another basketball team. j/k
Seriously, the first thing you should do is dust yourself off and gain your confidence again. If you can't gain confidence, you might want to simply ask yourself if you actually like what you do. Often people aren't very good at something because they haven't made it their own goal. Don't do it for your dad, your friends, your wife, or even your kids. While all of those are a very worthy reason, ask yourself if you actually love it because YOU love it.
Secondly, perhaps you scored really poorly on a particular section that somewhat correlates with your field of practice. If that's the case, I would recommend taking a course at your nearby college that offers a fresh look at the industry.
Thirdly, I would make sure that you have the CERM 11th edition and have every chapter tabbed. Make sure you even know the silly stuff like engineering economy and memorize that book from cover to cover. Now, when I say memorize, I'm not saying that you should know how many words are on page 64-9, but you should know every subject and have every subject located. 99% of the exam, as others have more eloquently pointed out, is about knowing how to find and apply the right information. That includes knowing exactly what they are asking for and knowing exactly where to find it in the big behemoth.
Fourth and lastly, make sure that when you put in the time next time that you have a realistic plan that you can handle - a plan that you can track progress by grading yourself. Make sure that your plan has been communicated with your family. If you are pro-active with those you love, they are usually more willing to make the sacrifice with you. BTW~a great way to grade yourself is by working through all of the breadth portions of the 6-minute solutions. People say they are harder, but not by much. They are very, very helpful and I couldn't have done so well on the environmental side of civil engineering had it not been for those 6-minute solutions. The CERM, in my opinion, should not be your only resource. All of the 6-minute solutions along with the CERM is the only way to go, especially if your struggling.
Good luck and God bless Lakersfan. At least you have an NBA squad to be proud of. ;o)