It starts with knowing your limits and communicating boundaries. Monitor how you felt before, during and after each interaction. Sometimes you may notice that it costs you too much energy. In that case, plan your get together, when you have most energy during the day.
If you notice that you have negative emotions or feel fatigue during the interaction, then that is a good indication that you’re at end of capacity.
Giving further emotional support to that person will make you exceed this capacity. Cut the interaction short and do something that boosts your energy.
If you feel tired or unwell, ahead of time, before your interaction, then it is time to set boundaries. Let them down easy and use assertive ‘I’ statements. State how you feel and if you choose to, when you can meet that person again. You can say something like:’’ I am feeling really tired today. I need some time for myself. Will it be ok if we will talk tomorrow?’’. Take more time to care of yourself. Do things that you find emotionally nourishing and or physically relaxing and soothing. At the end you will have more energy to care for the others this way.