You are being too hard on yourself. We all suffer from "imposter syndrome" but you seem to have taken it very hard. See the post from "yowlingcat" in this thre

You are being too hard on yourself. We all suffer from "imposter syndrome" but you seem to have taken it very hard. See the post from "yowlingcat" in this thread for a positive outlook. To add to the above, If you have already spent 10 years in this industry as an SWE, you cannot be as bad as you think you are. Yes there will always be much to learn and you might have some catching up to do but that can be fixed with studies and collaboration with coworkers. Do not give in to self-doubt and quit your job; particularly in these difficult financial times. Ask for help, mentorship and study/work hard and you will grow in knowledge and confidence.