Life has been a roller coaster since I started programming. One minute you feel like a god after solving a stupid type error the next you feel like a total idiot after not being able to solve a failed unit test caused by a typo. 24/7 you're a constant victim of the Dunning–Kruger effect.
It's really hard to understand how much you know about a subject. I've doubted myself countless times and was scared if I could even survive as a software engineer. But we always get by. Thats just the nature of learning and staying relevant in this industry. The key is to be humble but never doubt yourself. Keep on learning and never bottle up your problems. Ask someone about the problem you have and constantly ask for feedback, it will substantially help you grow. The more you grow the more you understand where you are and the path necessary to grow and succeed.