I had a very similar problem, Lumi. It was at its worst from 8th grade through college. I am better now that I was even two or three years ago though I suspect my husband thinks otherwise because he has commented on how he wishes his friends and acquaintances could see the way I am at home. It was worst in church and in some classes and lunch period at school.
I think the worst part about it is that it made me think was crazy or weird or that there was something "wrong" with me. Also, it confuses people and sends them "mixed signals" about whether or not you like someone else or want them around. My mom or someone told me once when I was "lamenting" my frustrations and getting angry at other people for not talking to me more than once or a few times, that I was sending them "mixed signals". I didn't really know I was sending them any signals and thought they knew I wanted them there because I looked at them and because I felt I wanted them and just assumed they could sense that. I wasn't fully aware of how I was "presenting" myself and how they were perceiving me. I had the added issue that there were some people I could talk really well to once or twice and then not be able to the next time; it confuses people. It took me a wry long time and my husband's observations to realize that a lot of that had to do with environment. I think he told me once that I often acted as if I didn't know someone in different environments. If someone was like that with me, I might be a little confused too. I was somewhat aware of it because I often worried that someone would think I was embarrassed by them around other people when in reality I mostly just had trouble "gerber aligning" my social interactions.
Something else I realized lately is that I would say something and no one would respond so I thought I was annoying them or said something not applicable or unimportant and that they were ignoring me, when in reality they probably didn't hear me. I am better at talking louder now and so have learned when I simply might not have been heard and whether or not I can repeat it louder, according to the situation. I used to have severe problems with talking loud enough. I thought I was really loud but no one else ever did. I am still told I have a quiet voice. This made the problem worse because when I did manage to speak, I thought I was being ignored which didn't helps confidence and anxiety issues.
I guess the most comforting thing I could say is that you aren't the only one and from what I have read here in similar threads, this is probably a common thing here on this website.