Welcome!

I'm sorry to hear that you are experiencing these struggles. I would encourage you first to seek some IRL support from persons with balanced long-term perspective on this stage of life, whether from among your personal relationships, or with a professional.

Secondly, may I note that Bs and Cs are not bad grades in rigorous university STEM courses, such as those in which you were enrolled. Also, in your previous posting you described yourself as second in your graduating class--hardly a horrible failure in high school. So please give yourself a little more credit for your objective level of academic performance.

Whether or not you met some arbitrary criteria for intellectual giftedness during K-12 school is much less important than the choices you make regarding yourself from here on out. You got yourself into a university in a challenging major, and had enough self-awareness to consider that you might need some time to work on other aspects of your being before proceeding further in your education. These are not the marks of a failure, but of someone who is thoughtfully considering how best to make use of their gifts and life experiences.

I would encourage you to take this time to explore the situations and pursuits which make you feel most like you are being both true to yourself and a contributing citizen of your community. When you have a moment that reflects even a little bit of this, try to identify what it is about that moment that resonates with you. Consider, perhaps, journalling those moments or otherwise keeping a record, so that you can periodically look back for patterns. Ways to explore those pursuits might include volunteering, engaging in a variety of hobbies, or trying out different entry-level employment situations with the dual purpose of subsistence (of course) and exposure to different career possibilities and fields of study -- not just in your own nominal job, but by observing up close how others' jobs work.

Beyond a certain point, your potential will be less impactful than your choices.

All the best.