I hate my job, do I quit?

I hate my job as a software developer. I am constantly asked to make nearly impossible changes to applications that are so old they hardly work. Making any changes on applications being held together by duck tape brings in so much risk and when things break it’s my fault. I like software development, but that part of the job makes me miserable. I just can’t do it anymore. Is this normal in the career? I want to quit and I’ve wanted to for many months now, but I’m pregnant. I won’t qualify for maternity leave anywhere else at this time, if I even get hired anywhere else. But I hate my life going into work everyday. I am stuck. I cry once a week because of work.