Kundalini is the life current. Or we might say the life force. When it intensifies or awakens itself our subtle body goes through many changes. Sometimes it happens after years of preparation and other times it is a spontaneous awakening. Sometimes it triggers shifts in consciousness that might appear to be depersonalization or a lack of personal identity.
You ask why anyone would want this. People who long for self realization have no control over the longing. It may happen before or after the activation of kundalini. It is like The sexual drive It simply arises at a certain stage of life in some people. Others never become interested and have a passion or focus or other things. It is not the ego that wants self-realization. It is the deep true Self wanting to be liberated from the contractions of the conditioned persona that a person carries, which is usually the cause of unnecessary suffering. Some say they want to end suffering. Some feel a need to know if there is a God or they are wanting to know the meaning of life. Most spiritual seekers do not realize the depth of the deconstruction that spiritual awakening brings, and the true nature of surrender, until they are very deeply engaged in the process It can move from great transcendence and bliss and joy to a feeling of falling apart very quickly. It is not a mistake when this happens. It is the just the way it works for most people
If you have seen clearly that you are not the separate self but are the life force or universal source or spirit (whatever you might call this which is unnamable), and know you are only wearing the cloak or playing the role of a human identity, the mind might react with terror or sadness or some other emotion to pull you back into old patterns. This understanding is very threatening to the ego structure. Some people feel pulled back and forth for years between old patterns of identification and experiences of pure consciousness
There is no question that when awakening happens there can be a loss of drive and of interest in the things you used to enjoy and identify with. This is a very common concern. It is like a whole layer of who we are just falls away. Most people have to find their way into a new way to live. It helps to remember to just be in the moment with what is with consciousness and heart rather than thought. It helps to get out into nature or to explore a few activities you feel drawn to. It helps to set an intention of living in a way that feels intuitively authentic for you and give up concerns about what other people think. You may realize that how you see the world is not the way the mainstream of our society sees it and this can feel lonely to the mind, so it helps to find community and read teachings by those who share your perspective. You can reenter society, work, school, and old activities but you may not feel as engaged in these things as you did in the past. If something feels important or right to do you can learn to consciously lean in and do it even if there is an underlying detachment. This feels better than complete lack of involvement in life. If you do this you will eventually find those activities that are a good fit for you. It is like learning anything. You can learn how to live with life and enjoy other people even though you feel somewhat uninvolved. You can find joy and compassion and curiosity and love in new and unexpected ways, especially if you are just present in the moment with what is! If you can allow your heart to be open, eventually there can be a deep relaxation in just being who you are with no concern for an image and the end of a running dialogue in your head about what you should or shouldn't be.
Often those who go through these changes need to be more grounded, more fully present in their bodies. You can use your intuition about how to eat but it is very helpful not to use intoxicants or drugs and to be sure you get enough protein. You may feel inclined to be vegetarian but if so plan a healthy diet with protein it. Your general health and any challenging issues with digestion may require dietary changes everyone is different in this regard so I cannot make specific suggestions. If you have concerns you might see an Ayurvedic practitioner who can look at your body type and energy and tell you specific suggestions for balance. If there is a lot of energy you may feel extremes of hunger or no appetite at all for a while. There are numerous variations in what the body wants and needs at this time. If the energy is very intense some yogis recommend drinking warm milk with sugar and ghee in it, saying this is a calming drink, certain herbs and oils help with calming the energy down and some yogic asanas are useful for stretching and opening the body so that the energy becomes more harmonious. Many people feel a need to avoid stressful and crowded environments, at least temporarily
You may feel you have had an experience you would like to avoid, feeling you had no true desire for it. But in fact something drew you to the practices that triggered it Even though the result was not what you had thought it would be. You can try to reenter your old life or you can look for the teachings that will confirm your experience and support a new kind of life. You can see the experience as a great blessing and a gift of insight meant to happen in this life or you can put it on a back burner and see it only as a passing phase. Often spiritual growth takes place in spurts and a deep experience is followed by some years of ordinary living and then another leap happens later in life. I would say that is how it was for me, with several distinct stages between the ages of 28 and 60. Everyone has a unique journey in this process that is really only leading us back to our Self, which we come to see was here all along.
You might find the writings of Adyashanti ( esp. “Falling Into Grace” or “The End of Your World”), or Jeff Foster (“An Extraordinary Absence”)helpful. Both had awakenings as young men and describe their way of finding how to move in the world through their writings.