A flash of idea popped up in my mind, and this 16-bar melody looped for a long period.
The first melody composed seemed somewhat familiar, like some sort of inspiration or a direct reference from a piece melody.
(one is evident, Pachelbel - Canon and Gigue in D)
Anyways, enjoy a moment of music brainwave
(Feel free to comment what did I reference by an accident.)
is good how you put the dominants and the thirds:
in this case, this piece should be in C♯ and the third is F minor;
yhe dominant is A♭ but you already know these things.
Very good job!