Crying occurs when the body reacts emotionally to something. Tears are a reaction of the nervous system to try and ease our pain, just as we would when physically harmed. The body senses our distress and the cranial nerve in the brain is stimulated, this sends signals to the neurotransmitters in the tear glands to make us cry. These tears contain high levels of manganese and the hormone prolactin in order to reduce the amount of these chemicals in the body, a defence mechanism produced to keep depression away. This is why many people feel better after they cry, because these excess hormones have been reduced and the body is returned to a more stable state.
Sometimes we say we can’t cry anymore. Why? Well, if you keep triggering a stimulus, the nervous system stops responding. If you keep pressing on a bruise, after a while the nerves won’t respond anymore and it won’t hurt. If you keep getting upset, the body might not react to it, you might not cry, and you probably feel worse.
So if you need to cry, just do it. It might be distressing, it might make you feel weak, it might make your eyes puffy, but it also might make you feel better.