While the landscape may be broad, it should be exciting that you can spend your entire life studying one facet of a subject as deeply as you like and there will still be an infinity of other truths you could have discovered. Talk to colleagues studying other fields, even if you never have an amazing cross-discipline breakthrough, it is nice to hear about other elements of mathematics.

disclaimer: While I finished my degree in mathematics, I immediately entered the field of programming, which was what I had intended to study.