How to handle unexpected emotions?

Is dad on Hospice?
If so the Social Worker and or the Chaplain are great people to talk to.
Hospice also has grief counselors that you can talk to.

You are lucky, your dad is lucky
You have a father that means a lot to you and obviously has been a great dad, role model. There are a lot of people that do not have that.
Your dad is lucky that he has a loving daughter.

When I was caring for my Husband I was sitting at his bedside and I was talking to him and I was crying because I knew he did not have much longer. then I realized that the tears I was sheading were "selfish" ones.
I was crying because I would miss him
I was crying because I was losing him.
I was crying because... I, I, I...it was all about me!
This was no longer the happy, smiling, blue eyed man that I fell in love with, the one I still loved. This was a shell. the blue eyes no longer sparkled, the smile was long gone, he no longer laughed, he would not want to live like this!
I told him I would be alright. I told him that I love him, would always love him.

I had known for 12 years, when he was diagnosed what would happen.
I had Hospice, they helped a lot.
I was prepared.
Or I thought I was prepared.
The morning that he died I felt as if someone had ripped my heart out of my chest and stomped on it.

Just take this time to talk, hold hands, tell him that you are there and thank him for being a wonderful dad and let him know that you will be alright.

You are grieving the slow loss of your father. It's called anticipatory grief. I would seek out a good therapist or counselor that deals with grief, along with Grief Share which is a support group for those grieving.
Watching the slow decline of a loved one is heartbreaking especially when you know there's nothing you can do about it.
Please take care of yourself and reach out for some help with your feelings which are quite normal.
God bless you.

I went through this as well. It’s emotionally exhausting to be a caregiver. Your feelings are completely normal.

Have you spoken to a therapist about any of this? I did go see a therapist and it always helps to get an objective viewpoint on what is troubling to us.

Best wishes to you and your family.