I don't want to do this anymore...

I'm so done . I don't want to try any more . I've always been positive but I think I've hit my limit . my mom is so fertile she got pregnant while on birth control even had 5 kids . my grandmother got pregnant 3 times each about a yr and a half apart. So why am I having issues ? On top of that my sister in law pops out kids like it's nothing but the dad's (3 dad's) take care of them . on top of that my half sister has 2 babies and both taken by cps because she's an unfit mother . wth??? What's wrong with me ??