Pregnant with 2nd child before age 21 and feeling like the world is against me.

It could be the mood swings, or it could be just the devil getting in my head. I want to happy about this baby but I can't help but think about all the negatives. All the things I haven't even done with my life yet and I'm already pregnant AGAIN. Now that I know what it's like to have a child I know what to expect and all that could be beautiful but I also know all that could go wrong. Family couldn't be more thrilled about this baby (sarcasm) they make it evident that they feel I am making a big mistake by having another baby. I am married this time around but I am still young. I can't help to realize that I'm following the same mistakes my mother and grandmothers made. Which makes me wonder, is this the right way to go about things. I'm trying to be strong and determined.