It's the same with your emotions. When your mind is taking on too much information or too many sensations, it's working twice as hard to maintain a semblance of normalcy for your body.
Emotions can get pretty heavy, sometimes, and your mind can't take the pressure. That's when your body starts to reflect the effects of processing your emotions.
This is why you feel emotionally drained; your mind and body are taking on too much, and the only way for you to fix it is to solve why you're feeling that way.
What makes you feel emotionally drained?
There are many reasons why your emotions are throwing you for a loop. The problem is, most people can't pinpoint the cause. This is, largely, because they are so used to approaching things the same way. They don't realize that their routines are causing them to feel mentally tired. Here are some examples.
a. Romantic relationships. A toxic relationship with your significant other can drain you emotionally, because you exert too much effort just keeping it afloat.