i was told the same thing by my doctor a few years ago. i was in my disastrous freshman year in high school, and my mom took me to see many doctors and psychologists. but I went to a homeopathic doctor specializing in natural remedies. he told me its not all about hormones, but when you're young your "neurotransmitters" can become depleted. that means that the messengers that control your feelings to your brain become distorted, which results in "emotional imbalance". lol. so he told me its not all about my body's chemical & hormonal changes, it's got a lot to do with how your brain is handling it. He told me I needed to eat and drink a lot of fruit and fruit juices, and he gave me some Neuroreplete vitamins. It actually worked alot. lol. I know that wasn't your question, but I have heard hormonal imbalance WAY too many times.
A hormone imbalance is when there is too little or too much of a certain hormone in someone's body.