What can I tell my mother to make her feel better?

Okay, so my mother has two kids (me, I'm 21, and my five year old brother), and we both live with her and my dad. She didn't plan on having anymore kids because her health has really deteriorated since her pregnancy with my brother and having another child could potentially kill her. She's in her forties. Recently, my Dad lost a good job making close to 100K a year, but he was forced to leave this job for another and take a pay cut of 30K, so he's only making 70K now, and between him and my mother's paychecks (mother makes 30K a year), we are barely making it because my parents have a huge pile to debt to contend with as well. I am a college student with no job and will be leaving home this fall for college and be living with my aunt. Just this weekend, Mom told me that she thinks she is pregnant because her breasts are very sore (she said that hasn't happened since she was pregnant with my brother), and she's very upset over it because she says that she and my father cannot afford to have another child and she is worried that it may also possibly cause her to die. I told her that if she felt that bad about this, maybe she should consider having an abortion, but she told me that she didn't believe in abortion and I completely understand but I didn't know what else to say because of how upset she is over this. She keeps telling me that if she's pregnant, she doesn't know what she's going to do. I'm suppose to get her a pregnancy test first thing tomorrow morning , and we won't know anything until she gets home after work tomorrow, and if she is pregnant, my father will also be very upset as well she says, but can someone please help me. What can I say that will make her feel better about this? What should happen if she's pregnant?