I'm so, so sorry OP.
I lost both my parents within 9 weeks of each other earlier this year. I too was a Daddy's girl and my Mum was my best friend. In the days following my Dad's passing, I distinctly remember being convinced that I wouldn't be able to physically bear the loss, the grief and the absolute searing pain that I felt. Then Mum died and it happened all over again.
In these early days, the crushing grief you feel right now really will seem unsurmountable, but you WILL cope and somehow you'll stumble into another phase, and the next phase and so on. Sometimes, you'll go back to feeling you're right back at day one and you'll doubtless have days when you feel just as raw and destroyed as you do now. But somehow you'll muddle through, and the next day you'll feel different - not necessarily better or worse, but always subtly different.
I'm no expert at grief but after this year, I'm an expert at crying my bloody eyes out. The only thing I've learned is that there is no timeframe for grief, no consistent shape or form to it, and sometimes it feels there's no room inside you to cope with it. Oh, and it's utterly exhausting...
Talk, talk, talk - to anyone, anything and at any place. I literally talk to the wall sometimes. Lean on people close to you and allow them to help you heal. Tell people what they can do to help you, it helps them to help you. At some point, someone will likely say 'take one day at a time', ignore them....when things are REALLY bad, just take one damned minute at a time and literally focus on getting through that minute, then you can worry about the next.
I appreciate it's not everyone's bag, but I signed up to Sue Ryder grief support text messages and personally, I have found their 2 or 3 messages a week enlightening and really helpful. Might be something to have a look at?
My heart goes out to you x