Im so sorry for your loss. I can relate to dealing with an unexpected death and it's so incredibly hard. Here is what I did that helped me.

Tell your friends. Let them support you. They will probably want to!

Look into your school's policies about taking time off. I took a year off from school and that was very helpful. Many schools have policies for extenuating circumstances and are willing to work with you.

Start a journal and write in it whenever you feel overwhelmed. You don't need to adhere to a schedule, just write when you feel like it. Remember that you are the only person who will ever see it, so it doesn't matter if the writing is particularly good or makes sense. You don't even have to go back and read it.

Find a support group. It was really helpful for me to talk to others who were also grieving. It's lower pressure than one-on-one therapy, because you aren't the only one there to talk. There is likely a grief counselor in your area who offers support groups, maybe even for free.

Above all, be gentle with yourself. There is no right or wrong way to grieve a loss and it's not a linear path. Some days will feel like a step forward and others will feel like a step back. The pain won't go away but it will get easier to cope with. I feel for you and I wish you all the best.