Is it normal that my adviser presented my work at a conference while I was there?
It is normal assuming (a) your advisor is actively involved in the research project, i.e., would be a co-author on any publications coming from the work and (b) your advisor acknowledged your role in the research during his/her presentation. For most faculty advisors (at least in my specific STEM field), much or all of their research is done with advisees, so any research talk they give will likely describe work done with others. 

For reference, my advisor gave a seminar in my own department on a project that I led. I had no problem with this -- it was nice to get their perspective on my work, and they acknowledged that I had done much of the legwork.