You can't let go of what makes you sad because it once made you feel so delighted. You can't and you won't ever try to move on in the first place because you still believe that things might change and it will make you giddy all over again. But as the time goes by, as you go through the process of detaching oneself from that person which is a very disturbing phase of moving on.
You are reminded of all the delightful memories that you had with them but at the same time those memories becomes morbid to even comprehend. You are reminded as well that what you thought was making you joyous, was never the right thing. It comes as whispers from your conscious mind telling you that the memories you valued most was wrong and everything was a lie.
A somewhat alternative reality composed of cobweb of lies. Made to somewhat manipulate you into thinking that they are really interested in you. You kept insisting that there might be things that are real.
You are in denial that at some point the things you thought aren't lies. It felt dreamy and felt like it's real but you were just dreaming while your eyes are open.
Now you're aware that what you feel is the process of detaching oneself to the person who you love so dearly but didn't loved you back.