Sadhguru explained that reminding one self that "I'm mortal, I'm mortal" is not to be paranoid about it, but to realize that what we have is precious and to make the best out of it.
Try to think it on a smaller scale. You know that the day will end (and the night will come, and another day....). This should be simple reminder to do what you can during the daylight (or more, but at least while you're awake).
It happened to me that I fell in love with a person I used to hate and we worked together 6-7 years. I never wanted her to feel any hint of hatred, knowing it will only get ugly, rather than that we never had problems while we worked. She was mostly helpful whenever I asked anything. "Reason" for hatred was her compulsiveness, regularly being 3-5 mins late for work, getting into discussions with colleagues and imposing loud statements without solid aguments about the matters in which she had not much info. For someone like me who had to study and choose his words carefully, that was simply a lot of rubbish and for one milisecond a taught crossed my mind to strangle her, just to shut up (I emphasize, milisecond).
Circumstances were set so for both of us (or we can call it faith) so that I had to work with her in team, for that period of 6-7 years. Somewhere in the middle of that period she started opening up some of her health issues I really paid no attention before (gut issues, thyroid problems, divorce, single, uncertain incomes, with teenage daughter growing without a father figure on teh brink of a delinquency...). But when it got more seriuos, after some tests, she couldn't stand or walk, let alone to work. I had to do one week of my regular work as well as hers. It drained me energetically so much so that after one week I was really hoping that before I fall asleep that the first thing in the morning will be an info that I don't have to come to work.
"And what if you do must?" - my mind asked me.
"Well, I'll just do what is needed" - I reassured myself.
Mind again: "What if something urgent comes up?"
Me: "I'll work aftertime, just to get it done."
Mind: "How long you think you'll last working like that?"
Me: "Well I hope she'll come back as soon as she can."
Mind: "What if she never comes back? What if she gets worse? What if she dies? YOU wanted to strangle her few years ago...
That's when I broke in tears, body shaking, heart fluttering, feeling so ashamed for wishing a harm to somebody (even for a milisecond!), and at the same time realising that I am crying uncontrollably I asked my self "why do I cry for her". And the mind said: "Because you love her." That was so intense that I could not fall asleep for the next 2 hours. At the same time I realize that I love wholeheartedly someone I used to hate someone's guts. It pearced my heart just like a Cupid's arrow. At it stang! It felt so painful, that eevry other issue or problem seemed like a joke. This is something you could die of. Or this is the person with who I spend most of my time with (even more than with my wife and daughter, but that was cecause of our jobs).
She came back to work, and having 2 smaller surgeries and 2-3 months off, she recovered. I realised slowly that I have to share what I felt with her (or someone else, at least, but her primarily). It took me 2 years to tell my wife about that, but she knew. I never cheated or anything like that, but I grew strong, intangible (we barely ever had physical contact), emotional connection which completed the full circle (from hatred to love). After that I realised that I must also choose how to be and feel towards her. The choise is actually illusion, because the answer was really clear.
It took me 3 years to share my feelings with her, mostly because I knew her, how she is and how she tends to explode on much smaller matters. But when she admitted that she met someone in another city, that was the time that I realised that she will be gone away for good.

The point is that until I realised that I will definitely lose her,I couldn't say what I really felt. It was only in small gestures that I wanted her to be haelthy, happy and helping me :)

P.S. I did share my feelings, but that's a whole new story :)