What's an example of a tough CS question? Maybe you're getting shot down because the interviews you've been getting are unreasonable, or maybe you're getting shot down because there's a real deficit, at which point you'd need to make a decision between a career in software or something else. Both are equally plausible scenarios.

There's nothing intrinsically meaningful about your CS grades, so let's not interrogate those.

You're too young to have anything "completely destroyed" by a GPA and a couple bad interviews.