Dear Anonymous,
I can't say if this is kundalini without knowing a lot more about you. But generally kundalini energy begins by what feels like an eruption of energy moving up the spine or from the feet and causing involuntary body movements. You are experiencing shifts of consciousness, which are often experienced in what is called "awakening" where one begins to experience themselves as pure consciousness and realize that everything is this, and where the boundaries seem to dissolve. This also happens sometimes when people use hallucinigins like LSD or mushrooms, or pot. Some people experience it in a way that is called disassociation by therapists, and this is a psychological condition that especially occurs when someone is under a lot of stress or anxiety or unconsciously wanting to avoid something that is difficult to face. It happens often to children who are being physically or sexually abused. And a few people just naturally tend to experience it. (These are kids who are called day-dreamers in school or who seem not quite present in their life). If these kinds of issues are up for you it might be wise to speak with a counselor or therapist. If not, and the experience is an aspect of spiritual awakening, perhaps if you stop doing any concentration practices and you get more grounded in the world -- making sure you eat well, avoid intoxicants or drugs, spend time walking in nature, doing physical activity i.e. sports or dancing, the phenomena may stop or become less frequent. Since it is already fading away I think there is a good chance it will pass, at least for the time being. However, in many cases once kundalini activates it does not stop moving through the body and one feels tingling, vibration, involuntary movements and other odd experiences at least occasionally. These do not harm you but they feel disorienting until you get used to them. You are also experiencing what yogis call sense withdrawal, where you do not feel clearly the sensations in your body. This is experienced when yogis do certain types of breathing and concentration practices and is part of the path of some yogas which lead to the realization of Self as pure consciousness.

Since you are young and starting school and since your experience is more about shifts of consciousness than energy events it seems possible you can move out of this experience if you just put your attention on other things. This is called "grounding". Getting more in touch with your body connected to the earth!

You ask where this is going. Ultimately a spiritual awakening leads to a felt sense of being in the world but not of it, although paradoxically knowing the body/mind as part of nature. It's a sense of being a spirit embodied. It opens up compassion and appreciation of beauty and love as well as an acceptance of what is. In the end it makes you feel kind of empty and quiet inside and this feels very free and open. But it usually dulls the drives and egoic motivations that are so much a part of western culture, and pulls one more toward a spontaneous and intuitive life lived in the moment. This experience happened very suddenly for Tolle, who I am very familiar with. But he was an older person at the time with his schooling behind him. Almost everyone else I have ever met or spoken to have spent years in this process, after awakening, and only gradually coming into a natural and comfortable life. If you feel you want spiritual direction and awakening at this time in your life I recommend you connect with the website, as Adya is a teacher who speaks very clearly about the process of awakening in ordinary life. His books and tapes could be very helpful. These changes are much easier to deal with when you let go of fear and just see them as part of your own growth process; in the way that going through puberty changes you, so does the awakening of energy and consciousness.
If you want the experience to stop, the most useful things you can do are to take good care of your body , learn more about spiritual awakening, get involved in things that interest you, and stop doing any practices that seem to make you uncomfortable. You might try working in a garden or on cars, or baking bread -- concrete, sensate experiences. If you want to follow this new spiritual direction the suggestions are the same but you may also want to learn a little yoga (telling the teacher you need to ground!) and learn to relax with the process, substituting curiousity for fear.
I wish you well on your journey. Bonnie