And somehow I always guess wrong 
Off topic but sometimes I like to just zoom in on your pfp and watch it do an achoo
Oh yeah I feel that. Sometimes I got to compose myself before I lose sight around me and just get lost in my rambling or emotions at the given moment. Many a time I realize its too late.
This happens to me way too much, many situations are just too overstimulating for me, to the point where my name has to be said multiple times for me to realize that I'm being talked to, and not someone else.
Body language, maybe. If you are welcomed in a conversation (and standing still) people will likely have their bodies turned to you and everyone else who matters in this convo. Similarly, you can pay some attention to people's feet, if they are pointing towards you, they are noticing what you're doing, if that happens during a conversation they are probably open for your input as well.
Yup! pretty standard situation for me. I try not engaging unless it is very obvious that I am involved in the conversation. It doesn't always work, but I try. When I'm at work I tend to leave my headphones in/on as a way to tell others I don't want to be bothered, and as a way to keep myself disengaged from the conversations around me that I'm not part of.
