Simple grounding exercises, repeated as often as needed. Here are three:
1) Find five visual, four auditory, three tactile, and two olfactory sensations. Then add one more for your taste buds – take a sip of tea, or really taste a piece of chocolate.
2) Count the different colours in your surroundings.
3) Create a peaceful place in your mind. What can you see? Are there people around, or animals? Are you seated, or lying down? What’s the weather like? Can you hear the wind or the rain? Are you outside, or inside? Imagine a comforting smell and the taste of a favourite food. If it’s too difficult to create your space without help, try this recording.
If it’s people that are stressing you out, it can also help to imagine you’re just watching them, as if they were on a TV screen.
Good luck.