Japanese (japanese dramas are usually easy to marathon because they are shorter and more dynamic than korean ones.)
Gokusen - judging from what you have already seen you might like this one. i consider is sort of classics of the genre. it is very enjoyable
LIAR GAME - if you enjoy mindgames and mystery i rec this!! :D
Love shuffle - quite cute romantic drama where couples decide to swich their partners and stuff happens
Korean:
Reply 1997 - my all time favourite drama, probably the only drama that i quite literally marathoned (during my exam season. haha.). first episode might seem a little weird but you will get used to it (or i hope you will :D). has little 'mystery' element that will keep you on the edge of the seat and forces you to watch next episode :D
Who are you: School 2015 - drama from the 'school series'. this one also has little mystery element (this time actual mystery) that makes you want to know what happens next. also there are new young actors that play really well.
Marriage not dating - in my opinion the best 'pretend relationship drama' (which i absolutly love) with great chemistry and good actors
Korean movies (i feel like sometimes a good movie can very well get you from your slump :))
Sunny - one of my all time favourite movies :)). gives me this 'feel good feeling'
A werewolf boy Hello Ghost - it is funny but at the same time kinda tearjerker :))
100 days with mr. Arrogant - very funny movie :D
