Wow! So sorry to hear you had this experience. I do not know what the cause was. It sounds like you are on top of you water intake. Good job there! I am glad you plan to take electrolytes, but just remember that taking them after class really doesn't do much unless you take them every day (in some form). I usually mix them in my water when taking or teaching a class. Other factors can affect your level of hydration. Lack of sleep, Stress levels, smoking, drinking and caffiene, foods heavy in sugar. Nausea can also be caused by eating close to practice time. Try not to get overwhelmed by all this

It takes a while to find out what your body needs. Don't give up and trust that you will find the natural rhythm for you and your practice.
Keep us updated about how things level out and any realizations you have
