You do not need an additional degree or coursework. What likely held you back was low clinical experience. You will need more than 100 hours, so I would recommend waiting a year to apply.
How many hours of non-clinical volunteering did you have for each of the activities you mentioned? The IAs are not a major red flag, just ensure your explanation for it on AMCAS was about you accepting your mistake. Do not bring it up again in your personal statement or other essays. What was your school list?