ChatGPT unusual error messages and sidebar

When I use my own ChatGPT account today, I frequently hits the error “Only one message at a time. Please allow any other responses to complete before sending another message, or wait one minute.”. But only me is the user of my account, and I never share it, I changed my password after that for security concern, but I still sometime get that message. And after some times of reload (before changing my password), I saw on the sidebar some weird chats name, and clicked on it but it said “Unable to load…”, then I reload the page then the normal sidebar is back. Does those signs shows that my account had been breach?