Sorry for your loss. My Dad died when I was 21 (about 12 years ago), it was sudden though not unexpected. He had been ill for a while but I hadn’t expected it to be so sudden.
All you can do is hang in there. Its tough, and tough to have to sort out the practicalities when you cant really think and just want to grieve. Let your friends and family help and offer support however they can. Don’t feel guilty for any moments of happiness that you may be able to find. Remember that it will get easier however much you are struggling.