My kidneys (and maybe my heart) are down to 10% functionality

I’m feeling...ugly lately. Not physically ugly, but emotionally. I like to think of myself as an intelligent person. Someone who realizes that everyone has their own problems and issues in this world and just because one persons problems seem big, that doesn’t diminish or minimize another persons. However, even in knowing that to be true I can’t seem to stop myself from being bitter toward so many other peoples situations. Social media is what is bringing out this realization in me. I’ll read a post on Facebook from someone about their bad day or their stress and think bitterly to myself “you have no idea!”  An example, you say? Alight, here’s one: a woman is pregnant and is complaining on FB about her swollen feet. My thought immediately is, “well at least your swollen feet will go away in X number of months and you get a new baby out of the deal. My swollen feet are cause I gave in and had  a cup of coffee today and I’m stuck with my problem for life. AND I likely will never get to have a baby so you and your problems suck!”
I am a compassionate person. I am good at being empathetic. This damn ESRD seems to have taken that from me and I hate it about myself right now. I’m sure there are people who would say to me “well, you’re going through a lot, your aloud to feel a little bitter.” But my having kidney decease doesn’t take away from the fact that the woman in the example has a couple of young kids she is chasing around already and she is tired and worn out from being pregnant and swollen feet DO suck. Everybody has their stresses and their hard times and my own don’t make theirs any less important or real. Why do I have to compare these things? Where did my compassion go? I hate feeling this way. I don’t want to be a lesser person because of bitter feelings toward my disease. But even in knowing all that, even in recognizing that it’s something I’m doing and something I dislike about myself right now I can’t stop from doing it. I read some post that says “lots of stress in my life right now, please send good vibes my way” and think to myself that person has no idea what stress even is. So how do I change that? How do I get my compassion back? How do I stop feeling so damn sorry for myself and start being grateful that there are ways to treat the disease I have? I don’t want to feel gross about the person that I am. I don’t want this bitterness to consume and control me. I don’t want the size of my heart to somehow be in correlation with the functioning level of my kidneys.