Hello,
During my masters Degree I was also confused. Now I'm working as an antenna designer in a huge company. What I learned is that the books can give you the theory and the background about how to analyze and to understand an Electromagnetic problem. What I advise you, is to work on an electromagnetic simulator like CST or HFSS to learn first of all how to design a structure. Use the books to have some rules or formulas to design the structures. Try always to design structures that you have the results by an IEEE paper or measured structures in you university (or CST examples), in order to compare your simulation with the results. Try also to have some detailed benchmarks on CST or HFSS. Once you learned how to use an electromagnetic software, you can use the books to get ideas of structures or to understand what is the mode or the phenomena that you have in your simulated structure. Don't be afraid, go step by step. I can tell you that I'm an antenna designer since 2003, and I'm learning every day something new. So If you are motivated, you will success.
Don't hesitate to ask questions. I can help you.