the only reason im hesitating to watch this drama is cause i feel like its similar to HJM and i absolutely hated HJM.

Only Similarity is  that the main protagonist having DID. But the narrative is totally different. 

I did not hate Hyde Jekyl and me, but i didnt not understand connect with it it thus i ended up dropping it. 

My main issue with it was that t was all over the place story and lacking of chemistry of the main leads. It was like they had their own identity disorder trying to compete/emulate KMHM. They tried to make the make the story mature and deep, but failed big time. Their story ended up being super uninteresting because it lacked that certain combination of depth in character (all 7 of his personalities plus all other chracteds), wacky set ups, great chemistry between leads, and entertaining narrative. Those are all present in KMHM.

Plus KMHM definitely embraces immature and crazy in the most entertaining and endearing way. So definitely watch KMHM. 

Agreed.  As others have said, other than the ML having DID, the two are completely different.  

I didn't care much for Hyde, Jekyll, Me... but absolutely loved Kill Me, Heal Me (it's one of my top-faves).  I definitely recommend that you give it a try. :)

I loved KMHM


ji Sung did an amazing job of playing 7 different personalities plus a hilarious bromance with Park Seo Joon when he was  playing Yoona's character.... I fell in love with the sexy bad boy character Se Ki the most