Can't get over the death of my father

I'm 22 and my dad passed away about five and a half months ago. A distant relative of my fiances just passed and while he felt fine at the viewing of his relative all I could think of was seeing my father lying in his casket

Of course I was there for my fiance though he hasn't seem as torn as some of the relative's closer family members. But I'm there if he needs me

My dad's death was sudden and unexpected. He had medical problems, sure, but not so badly that we were preparing for it. He had a stroke and didn't survive from it. I had to drive across two states, saw most of my family for the first time since I was 13. I had a bad relationship with my father and I regret not mending it. I still am hurting and mourning him it seems. What should I do to fix this? I've never lost anyone that close to me before.