Self diagnosing adrenaline surges are not possible, and no one here can diagnose you either. Since no diagnosis was given to you before, I am guessing that they considered you were overly critical of yourself and needed to relax.
The therapist is a good place to go back to, but this time ask the therapist what their diagnosis is.
Besides your therapist, have you seen your doctor about this? And as AnxiousNoMore said, adrenaline is an actual substance, not a metaphor -- there's no way you know if you're adrenal gland is overproducing and it probably isn't. Given your age, I'd recommend your parents get in on this. We can't tell you if this is anxiety, but know that lots of things can cause you to feel hyper -- food allergies, food intolerances (such as to dairy or wheat or MSG or gluten), hormone changes or imbalances, blood sugar problems -- lots of things. That's why I ask if, in addition to a therapist, you've seen a physician.
I am only 17 years old with no knowledge in the science psychology but I do have anxiety. What you described does not sound like an anxiety disorder. Again I am not educated and can not diagnose you but it sounds like a "mild" case of depression. Next time you see a therapist you should definitely ask many them questions and voice your concerns so they can tell you what you might be feeling.
Self-diagnosing any type of mental illness is generally frowned upon by psychiatrists. However, as a 21-year-old who has struggled with anxiety for many years, it does sound to me as though you are dealing with some form of anxiety. That being said, I want to let you know right away that there is nothing “wrong” with you. Anxiety is a common disorder, especially during the already stressful years of being a teenager.
The descriptions you gave about the way you have been feeling are common experiences associated with what is called a panic attack, which is caused by overwhelming feelings of fear and/or anxiety. You were absolutely correct by describing the increase in your body’s energy levels during these situations as “sudden adrenaline rushes”. Sometimes adrenaline is released when we are overwhelmed by anxiety or stress. Our bodies release adrenaline in these situations because our brains associate high-stress situations with being in immediate danger. If we were in the danger our brains often mistakenly think we are in, adrenaline would activate the fight or flight response in our bodies in order to protect ourselves. However, the release of adrenaline in non-life-threatening situations actually increases the anxiety we are already feeling, primarily by triggering common symptoms of panic attacks. These symptoms can include a racing heartbeat, trembling or shaking, difficult breathing, and/or an upset stomach, among other responses. If a panic attack causes an upset stomach, feelings of nausea, like you are experiencing, are not uncommon.
Feeling the need to hit things, throw things, or yell during or immediately following a panic attack is also common. The way our bodies respond physically to anxiety is almost identical to our bodies’ responses to anger. When we are overcome with anger, it is likely that our heartbeats will speed up and our breathing may become shallow, our bodies might even begin to tremble or shake, and we may begin to feel nauseous. All of these physical responses to anger can also be physical responses to overwhelming anxiety, which can result in our brains becoming confused about the difference between these two emotions and we may react to feelings of extreme anxiety with actions we generally associate with feelings of anger.
As I mentioned before, anxiety may be especially prominent among teenagers, however people of all ages struggle with it. Many people will experience anxiety for only a limited amount of time, whether it be during a particularly stressful few months in their lives or few years. On the other hand, however, many people are diagnosed with what is called “chronic anxiety”, in which case they will experience anxiety throughout the rest of their lives. However, having chronic anxiety does not mean that there is no hope and that the person diagnosed will forever suffer from anxiety. Learning specific skills, attending therapy, and sometimes even taking prescription medication can all help to keep anxiety from taking control of your daily life and to keep overwhelming feelings of anxiety at bay.