"I feel like I'm a failure. I should have been able to fight it".
Do you want to be a perfect demi-god or something ?
After reading the whole thread, all I can say is, whatever you chose to do, be kind to yourself.
Nobody expects anyone to take 100% of correct decisions. You always take the best decision because that's the limit of your current knowledge/experience. You're failing only to your inner critic.
Be well.
PS : I've heard MANY good stories about CS (not on the internet, just people on my city). Probably worth a try.