What do you mean by acknowledging their existence? My paranoia is that people are thinking I am being impolite. Though no one has confronted me or showed any hostility toward me looking at them, still the idea is prevailing in my head.

The following is related to this topic indirectly. For the language part, when you say you don't speak the language well, does it mean that you cannot manage a conversation, or you can manage but you have an accent?

For me, the language is a problem when it comes to speaking to others. I can manage (i.e., I can deliver my message), but I have an accent, too. These two things, not speaking the language perfectly (not using the correct words+not using the correct grammar all the time), accompanied with an accent, is something contributing for me to be more isolated. Like when I buy a ticket for a movie, I think that all people are listening to me, and make fun of me in their heads (some did in my face), not because of my nervousness, but because of my language, which makes me nervous.