😢😭😢 Rant/ My heart is broken 💔

The man I have called my dad my whole life and was married to my mom since my older brother was born in 1986 told me today he mite not be my father. I was born in 1989 he said my mom cheated on him around the time she got pregnant with me. I am almost 30 years old. I am 19 weeks pregnant today and i had to rush my almost 3 year old to the hospital this morning. Then he tells me this. My grandparents my mom's mom and dad said that the offered when I was born to pay for a DNA test my dad said no. My mom passed in 2013. My dad has never said anything about this to me in all my life. He started acting weird like this when his girlfriend came on to his life right before my son was born in 2016. I was living with my dad at the time with my husband and was made to move out after I had my son and she moved in. I just don't know if this is really him or her with all this bull shit. They also said I am a bad mom and should have my son and baby I am pregnant with taken away. My son is healthy, happy, and very well taken care of. I just don't know anymore. I am at a lost of words.😢😭😢😭