I don't know how to feel

I lost my Dad January of this year, and I still don't know if it's real, I never said goodbye, it was a sudden death, he felt unwell on Tuesday saying he felt rundown then was found dead on a Thursday.

I feel terrible for not feeling much at all, I loved my dad there was no strained relationship but I just don't know what to feel and I feel awful for not feeling so so sad.

Has anyone else felt like this ?