Welcome!
I just started seeing a therapist who uses a type of CBT called acceptance and commitment therapy. One strategy that she recently gave me that is helping me is, when anxious thoughts are filling my mind, to step back and say something along the lines of "I'm noticing" and then state what type of thought and/or emotions you have going on. I then tack on stating what the more realistic reality is.
For example, if I notice myself on a thought loop about a worst case scenario, I notice that I am doing this and then think of what one or two more realistic possibilities are. My "worst case scenarios" are usually pretty unrealistic so this strategy helps to reground me.