Mindfulness can bring focus to ‘being present in the moment’ and ‘crowding out’ anxious or negative thoughts.
There are many effective techniques that get stronger with regular practice.
Keep yourself ‘grounded’ with a pebble in the pocket or a comforting wrist band.
If home, slip-off your socks & shoes and practice mindful walking on your bedroom carpet or garden grass and focus your thinking on the connection between your body, senses and mind.
My favourite mindfulness practice is Body Scan and listening to the voice of Prof. Mark Williams.