On thinking about mortality

It's sometime around 7am when the lrt lurches to a halt and I'm thusly lurched out of my daze. Walk walk walk.
I've made this walk now something like 856 times. Though,  knowing me and my love of over exaggerating numbers, it's probably more realistically like 40 times. Back and forth and back and forth. In the 114th street doors. Out the 112. Cross 112. Get a coffee. Drink the coffee. Smoke a cigarette. Get another coffee.
My body - my stomach in particular - is not happy with my choice of living entirely on nicotine and caffeine. But I'd like to justify to it that I've only slept for 7 hours in the last 4 days and it's not actually a "choice" - it's a means of survival.
I'm walking past the same set of faces every day. The same sullen looks of disparity and fear. Black sluggish bags under every set of eyeballs that refuse to make contact as we silently cross each other over and over again.
I wonder about their lives. If they're having a bad day or got some bad news. If they're dying or their parent or child is dying. Worried faces lost and blending into a sea of other worried faces.
Intermixed every once and awhile I'll see a smile or a bouncing child that breaks up the bad news train and I'll remember stings of hope still mark themselves here too. And that's the part I should be hanging on to.
I don't know if I'll ever be ok with being old and being at the mercy of other people all day long.
In reality, my grandmother will get out of here soon and start a new chapter in her life as a bionic human who no longer gets to rely on just herself. And it's not about me or my ability to cope with that news, it's about her and how well she will adjust.
My feelings here, they mean nothing.
And if I spend an entire week or month camped out on the cold floor of a hospital room or riding the train at obscene hours to run home to change my clothes, what I feel still doesn't hold any bearing to the gravity of her life.
But I can't help but be changed by these days. My own sense of mortality has shifted and I'm scared for the first time that maybe I'm not as adjusted to life and the reality of loss as I thought I was.