I was put on hold for interview at UCSD and ended up not receiving one. Two other applicants I know faced the same situation. When I inquired a UCSD med school admissions official about the hold, she told me that only a small fraction of people on the hold list actually get invited for interviews. I wouldn't tell you to simply give up all hope, but know that there is a good possibility that you might not be attending to UCSD next year. On a brighter note, it would definitely help to send them more materials--more rec letters, updates on new activities, a letter explaing why SD's your school, etc.-- to trying to adorn yourself. Good luck!! 🙂