Member of my class died

Today I found out that a classmate of mine passed away from heart failure and it hit me so much harder than I expected. I wasn’t even that close to her, I just knew her as my friend’s best friend and someone in my class that i talked to occasionally. I feel so guilty that I wasn’t always talking to her or asking her how her day was. It hurts me to watch other kids in my grade to just carry on or people to be insensitive and I don’t know how to heal and move on because she had an impact on my life. I have to continue with junior year and push forward but I just can’t even think about doing classes the next few days. Sorry for the long post but I needed to vent to someone that is not a guidance counselor.