MC: Only Us by coovu

So yesterday,i read the MC: Only us by coovu.The other said that this story can be viewed differently by everyone. I would like from you,to write how you viewed the story.
I have kinda to meanings.

  1. A girl in a toxic relationship that feels ashamed of herself for not being good enough? Now they aren’t together anymore but she still misses him even though he is not right for her.
    2.A girl with a mental illness that isn’t in a relationship anymore because the other person couldn’t handle her.
    I dont think i understood the story but just some theories.Tell me about yours!
    Also the author said that the story handled two "mature " themes .The first one is suicide i guess,but what is the second one?