Nope, I've been there. Being a SAHM was a wonderful chance to be home with my kids that I wouldn't have traded for the world...but it was also becoming mind-numbingly dull after 3 years of it, and I desperately needed to do something more intellectually challenging than reciting the ABCs and changing dirty diapers! I wasn't ready to go back to work full time in an office or classroom again, but I needed more to my life. I definitely felt all those same frustrations and boredom and depression that we see in underchallenged GT kids. So yes, I see the parallels! Yes!
My solution was to write a novel. That might or might not work for you, but have you tried finding a hobby or a passion or some volunteer work that is challenging and fulfilling as the novel was for me? Just as afterschooling can keep GT kids from losing their minds, "afterworking" can help keep you sane without requiring that you "quit your day job."
Best wishes for more challenge in your life!
