'Aparigraha' Yama-Niyama

Regarding the aparigraha part of the yamas of the yoga sutra,I would like to ask you what really is aparigraha, the definition given is non possessiveness . However after starting practice I am in doubt how to implement this. After starting brahmacharya along with pranayama, I felt as if I have become a sanyasi, not totally but partially as i no longer cared about anything, not in a negative way like careless, but rather i became carefree, while I performed my activities. This was because of certain bliss like feeling which can be equated to taking cold shower, or rain or like thirst for water being satiated,though even this example dwarfs as compared to the bliss. I wonder if this is aparigraha . Just a curiosity which I hope you will satisfy.

Also there is another doubt, it is said that brahmacharya  gives a great strength, and that can be channeled into other activities, I have always thought/pictured it as the strength of a person fighting a life or death situation, with adrenaline rushing throughout the body, or a student studying hard for an exam with millions of competitors(again like a life or death situation) thinking of nothing else and completely immersed as there is no time to think of anything else. Is this an example of brahmacharic strength  or is this an example of raga(passion).

The second question has been asked because unlike the persons involved in these examples, I do not feel such strength but rather carefreeness while studying and making efforts when i go wrong, also once during as friendly arm-wrestling competition I did not feel the adrenaline rush but rather I performed it happily.