I'm a Vampire Lord but I'm getting pretty tired of being a vampire. If I cure myself but don't cure Serana will I still be able to become Vampire (Vampire Lord) again? Or will that be it of being a vampire?
Yes. If you've completed the Kindred Judgment quest and as long as Serana is not cured of vampirism, Serana can turn you into a Vampire Lord. You can repeatedly switch between curing yourself of vampirism through the Rising at Dawn quest and asking Serana to turn you back into a Vampire Lord, with no limits.