I have noticed in your post that you use a lot of extremes to describe your situation: eg. “I have always been I ignored”, “I could never keep friends...”, “I will definitely tank my interview...”, “no confidence, no sense of self”. Maybe that is truly how you feel right now, but I would find it unlikely that everyone has always ignored you and that you have never maintained any relationships. So I would recommend reflecting on some things that you are grateful for. It doesn’t have to be anything big, it could be the support of family, the understanding of professors, or your amazing dedication to school and extracurriculars.
Second, perhaps you can consider appraising your situation with more balance. This can be as simple as avoiding the use of extremes, like “never, always, none, everyone.” Although it may feel horrible sometimes, there is likely a silver lining and you can appraise the situation by trying to see both sides. Maybe no one noticed you in class in the morning, but you worked with some friendly people in your ECs in the afternoon. So acknowledge when good things happen and avoid seeing a situation as “always“ like this, or “never“ like that.
Third, if things don’t turn out how you hope, then take things into your own hands! As I’m sure you’ve learned in psychology, people with an internal locus if control uphold the belief that they have control over their lives and subsequently they show greater resilience when faced with challenges. So if no guy seems to ask you out, then why not ask them out instead? If you don’t feel like you belong, then maybe try exploring another group. If people are not taking the initiative to get to know you first, then why not take the initiative to make the first move?
At the end of the day, the interviewers will be looking to understand how you overcome challenges and that you are capable of working cordially with others. You don’t have to be best friends with everyone and you don’t have to be the life of the party.
So this might be a good opportunity for you to re-appraise your situation, reflect, and take the initiative to make changes for the future. Because as a doctor, you will likely face countless other challenges and the interviewers will want to see that you have the ability to question your own beliefs and to take the initiative to improve for your future patients.