Fear of developing a new OCD theme

Well, actually I've had this fear for a long time now, but now it has gotten slightly worse. Sometimes when I practice mindfulness I get worried that I'll get the sensorimotor obsession where I won't stop thinking about my breathing. It hasn't happened until now, but I have this fear that anxiety or a brand new mental illness will destroy and ruin a good moment, this case being an upcoming trip to Australia. And I suddenly panicked thinking that I will develop sensorimotor OCD. Before I was dwelling on my anxiety and now I am more or less dwelling on this! 😖