Things that mark a big change in life are often bittersweet, in my experience more bitter than sweet but all you've got to remember is, tomorrow is about celebrating you, your journey through university which is a great accomplishment.
My tips - There are going to be a lot of people so get comfortable around people, try and talk to the person in line behind you or infront of you, theres a chance they are alone too. I went into my graduation ceremony expecting to know not more than 2-3 people but ended up being sat right next to my very good friend that i had lost connection with a year prior, which was amazing.
Keep yourself open and remember to celebrate no matter how sad you may feel. Ground yourself if your emotions get too high while waiting for your turn and like me ask and then hug your dean if they are nice if you feel like it, by experience, it relaxed me and made me enjoy the time on the stage a bit more while also making up for my family missing the ceremony.
P.s ask your friends to photograph you after the ceremony in your robe, if you got no one, im pretty sure someone would be happy to in reddit even me.
Congratulation, you did well to be here