I know how you feel. I joined a large guild of over 200 people and attended about six times and in all that time probably only a few people spoke to me. I am also a quiet person and attempted to initiate a conversation on a few occasions, but find it difficult when I don't know someone. With such a large guild it was impossible to find the person I last spoke to the next time I went so there was never a point where I was getting to know someone better.
I may try another smaller (more personable) guild in the near future though now that I am retired.