19 and pregnant

Pregnant with my first baby , I'm due in March and I am 5 weeks and 2 days. I haven't told my father yet because I am kind of scared but my friend who is Also pregnant says that me and my boyfriend should tell my dad but my dad doesn't really like my boyfriend and Its crazy because my dad already knows it's just like he wants me to tell him but every time I want to tell him I can't seem to get the words out of my mouth. I can't tell my mom because she isn't here anymore. I want to wait at least for my first ultrasound but I'm just so stuck idk what to do? Anyone has advice ?