I'm sure that i didn't do that. I don't know but if someone from the same group could remove me he maybe did, but I don't think so. I asked people form my group if they had remove me, but they said that they didn't do that.
I don't know what to think about it
Yesterday I was talking to one person, who said that she tried to invite me to our group, but messenger's message was like I have already been added (but I'm not)
Other said that one girl (from the same group) has the same problem as me.