I had a job and was dismissed after about a week because I made everyone else tense. Part of the problem was that I apologized far too often, but that isn't really important. Basically, yes I have felt what you are feeling, and yes, emotions can be contagious. However, CiunAnam is also right; most of the time many other people are nervous. Just try to relax and try not to over-think things. It also takes at least two people to make a conversation (at least in most cases) so the blame may not rest entirely upon you. In social situations, finding a common ground is a joint effort, in which everyone needs to work together for it to work. It may not always be you who isn't pitching in.