As far as physical pain, probably when I had a hernia, but that was so long ago that I can hardly remember it. In recent times it was a few weeks ago when I had something (dunno if it was a bug or some kind of food poisoning), and I was vomiting and had massive diarreah for nearly 14 hours straight. I couldn't sleep and it was excruciatingly painful to be in anything other than the fetal position, and even that was moan-worthy. It felt like my intestines were going to explode.
Mentally painful, definitely when I was diagnosed with depression at age 13. Already a tough hormonal time with huge social/physical changes in my life, and to pile on top of it I was diagnosed with something I didn't understand at all and had no idea how it would effect me for the rest of my life, I was so confused and scared.
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