Hi, Onlyme2! Yes, I have felt the way you do, and, I think, I still feel the same way, as if there's a massive guilt just below the surface. Yet...
Depression happens. And it's indiscriminate, too.
Sure, if a 1000-pound boulder falls on you, it can do a lot of damage. But a 1/3-ounce piece of metal hitting you in just the right way with sufficient force will do as much damage.
I suspect no matter what anyone here says, you'll still feel guilty. Acknowledge the guilt feelings, but try not to allow them to prevent you from treating your depression as a
real illness.
Depression deserves your respect. As one reaching out and seeking help, you've won my respect.
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My dog

mastered the "fetch" command. He would communicate he wanted something, and I would fetch it.