If the interviewer says "We have other interviews to conduct and then back to you in few days", is it a bad sign to not get the job? I had an academic interview. During the interview, some panel members showed  positive body language. In the end, they asked me for a reference. After that, the main interviewer said that they had some more applicants to interview and would get back to me after a few days. I wonder if that means that they are not interested in me? Is that a bad sign?
It's not a bad sign at all. If they have more interviews arranged, they wouldn't be doing their job if they didn't interview them. They don't just hire the first person suitable for the job. They hire the best person for the job! This may still be you - or it may be the next person to be interviewed. 

Be patient, and they should let you know one way or the other!