Depression while pregnant

Ny

I need help ladies do u guys ever feel depressed my boyfriend gave me an ultimatum to where I had to choose between him and the baby he wants me to get an abortion or if I don’t he will leave me we just had our son together seven months ago and he said soon as he found out in July that I was pregnant that he wanted another kid now all of a sudden he changed his mind and he doesn’t want another kid so now he wants me to get rid of it but I’m already too far alone and he said that he’s gonna leave me alone and not help me so I haven’t seen him in almost 3 weeks now and I was I can do is just keep crying and I feel bad for myself I don’t know wat to do can someone please help me understand wat I’m doing wrong wat did I do to Deserve this in mind you are already have three kids here now this is my fourth child and I’m going through this pregnancy by myself without his help