You have a good idea working here, and for the first part of your story, you definitely do it justice. You write well and you've crafted an interesting POV character, one who holds our attention as she takes us through the events in her life.

Inexplicably, while you do such a fine job of crafting your scenes in the first two sections, starting with the third you abandon this narrative style in favor of one that allows you to cram much more information into your text, but with decidedly lower impact and interest.

In the first two sections, you bring your camera and microphone in close and allow us to experience the events as they unfold, giving us a "you are there" perspective. You craft the scenes in such a way that we naturally are compelled to utter those most desired of words coming from a reader: "Gosh, I wonder what's gonna happen next." Get your reader wondering that, they'll stay your reader and keep reading to find out.

Note what happens in the third scene:

Waking up every morning wasn’t any easier, but he was there. He was always there. He made sure I got out of bed in the mornings and was fortified with enough food to start the day. He accompanied me to all my classes before rushing off to his. He would always be waiting for me when my classes ended and we would walk home together. Most of my time everyday was spent together with him. He made sure I turned up for all of my appointments with my psychologist, ensuring that I was making progress. He made sure that I never neglected my studies, but also spent enough time relaxing and doing the things I love. He always made himself present whenever I had my ‘episodes’, talking to me soothingly and making sure I was okay before I continued my work.

Note the shift in perspective. Note how we no longer have any clear sense of the passage of time; it's all already happened and we're being given an after the fact summary. Note how often the word would appears. Note that nowhere in this paragraph are there any actual events taking place. Instead, we are given an overview of a class of events: Ezra waking Rianne and making sure she gets to her classes; taking her to her doctors appointments; how he always made himself available. As readers, we aren't particularly interested in things that would tend to happen, given a series of conditions being met (the conditional statements incorporating the would form of the verb). We want to see one event, one specific event, occurring in a specific time and place, where a specific thing happens.

You've already shown that you can do action and dialogue. If it ain't broke, don't fix it, especially if the fix does more harm than good. I can envision a whole series of scenes—none of them particularly long, but all focused on a single example of the elements you describe in passing: Ezra waking Dianne up and coaxing her to class on time; Ezra working with her to study for an exam; a scene showing Ezra in the process of "healing" her, cementing her broken pieces back together; a scene showing him filling Rianne's emptiness. Of course, none of these things would be identified outright. If we see an actual moment of healing take place, we'll be able to form the desired interpretation. And, through it all, moving in parallel, the steady deterioration of Ezra, noted by Rianne, but not fully grasped, until the scene where she walks into his apartment and finds him dead.

It's the old showing vs. telling dichtomy. It's taken as settled wisdom that showing is better than telling. This is not true. Telling is important. It's how you ride a subway uptown without making all the local stops that your reader cares nothing about. It's how you turn summer to autumn without describing each leaf changing color. Telling is great for conveying background information without resorting to a kludgy flashback. Telling is how you establish context. But showing is what you do when the scene counts, when the characters need to be center stage, working through the events right in front of the reader. You are telling far too much, and the effect is a narrative buffer between the reader and the events that you want to pack an emotional punch. If those events remain hidden behind bland summaries, and time is compressed into single conditional statements, you will be cheating your story, and, worse, cheating your reader. They might not notice it. But you will, when they don't come back to see what else you've written.