confused

I dont know what to do. Im only 17 and Im pregnant by my boyfriend but he already has a 7 month old baby girl and I know everybody in my family is going to be disappointed in me. When i told my boyfriend that i was pregnant all he said was is this what you want. I took five test so i could see if i was and im making a doctors appointment for tomorrow. I honestly dont know how im going to tell my family. Im keeping my baby no matter what.