telling my dad

So my dad never really approved of my relationship he's came to where he's accepted it but he doesn't care for him much. But he does keep asking when he's going to ask me to marry him. Mostly because weve been together three years and been living together for a year. Well a few days ago I just found out that I'm pregnant and I'm 20. I'll be 21 in march.  It's really nerve wracking to tell him and I'm really really trying not to put the stress on myself. I know he's going to be happy, but heartbroken and really disappointed. And he lives across the country from me. I don't know if I should tell him now or wait. My boyfriend already told our group of friends, his sister&bil, and his dad. I've only told my mom. (And my mom got pregnant and gave birth to me the same age as I will be being pregnant and giving birth.) and we're waiting to tell my boyfriends mom after the doctors appointment in a few weeks. So I feel I should tell my dad then, or now. I'm just scared because I know how he's going to feel and it makes me feel so bad. Any advice?