Giving up is not an option. Don't forget that, as long as you keep trying, you haven't failed. If your grades went down during only one semester, and there is a legitimate reason for it, then you can just work to correct the problem. When asked, just explain what went wrong, explain the steps you took to correct the problem, and point out your future progress. If you felt burned out or partied too much, consider seeing a therapist so you can address these issues and continue to work toward medical school.
Is medical school what you really want? If not, then you can give up.