Controlling My Thoughts

Hi. I am curious to understand how to manage some really toxic thoughts that I don’t seem to have any control over. A couple of examples, “What if this is the last time I ever see my daughter?”, “Today could be the day that I die” (as I am boarding an airplane). These thoughts seem to come out of the blue and I immediately try to change the thought. This resistance just makes me feel more out of control of my thoughts. Should I try to accept that these toxic thoughts will continue to come and are just part of the deal? If so, how do I feel that I have control of my thoughts, when clearly I do not?