Don't be too discouraged at this time. R&D is a very broad field and although ideally you should, you don't have to know everything. As I said, ang fundamentals (like math, science and engineering) are very important. As you gain experience, you become more aware kung anung babantayin in your area of responsibility. Kung ang responsibility mo ay PCB design and passing electromagnetic compatibility tests, mas aware ka dyan. If you are on a different area, less so.
What is important is finding a path to your desired field. And becoming really good (an expert) in that specific area is most important. Kasi kung expert ka in your specific area, you can command a high pay. And that's what this thread is all about, di ba?