I recently got engaged and haven't really told anyone yet except my FH's family, only because they were there when it happened. Little back story, my FH and I's parents used to be good friends, a silly dispute over some stuff came up (it's been over 10 years ago) and my dad still holds a grudge. For context we are 27 and 30 and have been together over 5 years and have lived together for 4. When we first got together my dad was furious, he told me he would disown me if I ever married him, would not attend our wedding, and would not recognize any grandchildren as his if we had any. My FH came over for dinner after that to try to smooth things over, my dad refused to come inside and eat with us. Over the last 5 years my dad has gotten a little better and being less stand-offish but still has never even had a casual 1:1 conversation with my FH at family functions. He also will completely disengage in conversation if my FH gets brought up - it's basically don't ask, don't tell. The rest of my family, including my mom really like my FH and think my dad is being ridiculous.
The amount of anxiety I have about telling my parents I'm even engaged is overwhelming to the point it has made me physically ill the last week. I feel like I can't even be excited about my engagement because I have that looming over me. And I feel guilty like I'm robing my mom of this "fun" experience because we want to elope to avoid all of the drama of everyone asking where my dad is if we have a wedding; I fully believe he will stick to his word. And to make it even better I am an only child, so I have nobody for backup. Any advice, words of encouragement, etc. are welcome - thanks in advance.