Iv'e had that frustration. You likely need more problem type exposure and there are a limited set of problems. Consider the following if you don't already have them:
1. PPI SE Structural Breadth 6 minute problems – Probably a little more involved than typical AM problems in my opinion so very good practice
2. PPI SE Solved Problems – Very good for PM preparation as the problems are a little more involved and difficult than what you will likely see.
3. PPI problems in back of PPI Concrete Design, Steel Design, and Seismic Design – Contains both AM and PM level problems. Also, example problems throughout these texts were very helpful as practice
4. PPI STERM example problems and end of chapter problems – These were helpful but not as much as others.
5. PPI Practice Exams VF & LF
6. McGraw Hill Practice Exams VF & LF – these were good but had a fair amount of errors in them so be wise about checking your work.
7. NCEES Practice Exams VF & LF
8. Many problems in reference text books. Examples are helpful for sure. Answers may not be available to practice problems at end unless you can get a solutions manual on Chegg or something. I used the following for each of the major disciplines:
a. Wood: Design of Wood Structures by Breyer, et al. 7th ed.
b. Steel: Steel Structures Design & Behavior by Salmon et al. 5th ed.
c. Concrete: Design of Reinforced Concrete by McCormac et al. 10th ed.
d. Masonry: Masonry Structural Design by Tanner & Klingner 2nd ed.
e. Foundations: Foundation Design Principles & Practices by Coduto 2nd ed.
f. Analysis: Structural Analysis by Hibbeler 9th ed.
9. David Connor’s Bridge Practice Problems VF & LF combined text - This and an understanding of AASHTO and where to find things should be all you need for AM bridge problems.