Your boss has just told you some news that disturbs you, but a phone call from your spouse distracts you. after you get off the phone, you have a lingering feeling that something is not quite right, but you cannot pinpoint what it is. likely you are reacting to the continued effect of:

It is likely you are reacting to the continued effect of "hormones".

Hormones refers to the chemical messengers in the body that show movement in the blood to organs and tissues flagging them to take the necessary steps they were intended to do. They can influence various procedures in the body, including propagation, sexual capacity, digestion, development and advancement, and even state of mind. People both have hormones, and hormone levels change and create as the individual develops and ages.  

quote is the answer your looking for.

the answer to your question is,

d. when a child was born.

-mabel < 3