I would try this method called Brain Wave Vibration - it only takes 10 minutes and I sometimes go to a quiet room in my office during work and clear my brain fog.
There's a routine here that really helps me:
I would definitely try "toe tapping." It brings your awareness into your body and brings your anxious thoughts down. It really helps me doing it about 100 times before I fall asleep, which only takes about 10 minutes.
There's this video of how to do it here: