Just go for it. For a person who loves their subject (and I'm guessing by your name "sciencegirl1" that you're in that category), a PhD is a chance to immerse oneself in their favorite subject while getting paid.
Sure, I had a horrible time in grad school due to personal problems and not getting along with my supervisors, but now I can honestly say that I love my job. I get paid doing exactly what I love. So yes, for me it was worth it. I can come into work in whatever clothes I like, at whatever time I like (most days), and stay as long as I like. So long as I get the work done it's fine. There are not many jobs with this kind of flexibility. And ultimately, we're contributing to society in a positive way.
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