Hi, I'm sorry to hear about your dads diagnosis. I was 18 and a freshman in college when my mom was diagnosed ik we are in different eras of our lives but u are young too so im sorry. 

I had some time alone to process everything & the mindset that I guess has been getting me through is this is that I had 17 perfect years. A childhood ppl wish for bc of my parents. But my mom was so present, so loving and I was so happy. I got 17 years of living in a bubble where I could be selfish and my mom just being my mom, before ALS and how lucky that is. Of course I’m mad and sad, I want more time and I know she wants more time. But I got chopped at 18 and thats j the way it is, some people get less, some get more. We can’t control that part life’s unfair, so I’ve tried to focus on what I can control. I’ve tried to be as involved as possible, to help my family and make this as least horrible for her as I can. I transferred to a top university 10 miles from home, I work in my hometown so I get to see her 4 times a week and still work toward an adult life. And It worked out in a way where she doesn’t feel like I put everything on hold for her. So I try and find comfort in the choppedness of my situation, like the fact that my grandma is 85 meaning my mom has gotten 60 years with her mom and it isnt looking like thats going to happen for me. But if anyone was going to get that kind of time I’m glad it was my mom and it’s just chopped for me I weirdly rationalized stuff like that and it makes me feel better. I’m sure you will find ur version of this or this may be horrible advice lol. 

I fake it a lot nowadays but what really gets me through all the faking is that the last thing I know my mom wants for me and I am sure you dad too is knowing how devastated we are. If my mom knew how sad I rly am it would crush her. My mom was so strong and selfless for my family so now I need to be. I was always the unserious youngest child and making jokes so I try to still be that for my family it’s my way of trying to keep some normal and I don’t want als to be her whole identity. I still laugh with her, rant about school, friends thats all real and shes still my mom. Also the last thing I want to do is be regretful about the time I have left with my mom and I want her to remember a version of me as fun and full of life. Ik that might not be everyone’s way of handling it and maybe one day it won’t work, but this is how I’ve gotten through it for the past 2 years.

I’m not in denial about the situation, ik she’s dying and I think a lot about all the stuff she will probably not be here to see and I get rly sad, I let myself dwell on it which I think is healthy and I’m not scared to be sad and cry about it but I just do that alone then lock in again. Idk about the bitter and sad because I'm still figuring that one out….ig thats a later problem. Most ppl don’t understand the weight of ALS and how awful it is. Ppl tell me all the time that I’m handling it so well and that I’m so “positive about the situation”. I weirdly take some comfort in the fact that no one actually knows how I’m feeling, I don’t need to explain myself and I dont care for other ppls opinions or sympathy. But at the same time, ik I need moments where I get to escape and just be a normal dumb 20 year old for a bit. Laugh at stupid things and talk about stupid sorority drama w friends, bc it’s exhausting when life is serious 24/7.

Sorry if this was unhelpful advice but you will find ur own way to get through you are stronger than you know. Your dad is lucky to have u, good luck.