In the stillness of your presence, you can feel your own formless and timeless reality as the unmanifested life that animates your physical form. You can then feel the same life deep within every other human and every other creature. You look beyond the veil of form and separation. This is the realization of oneness. This is love.
In the egoic state, your sense of self, your identity, is derived from your thinking mind - in other words, what your mind tells you about yourself: the storyline of you, the memories, the expectations, all the thoughts that go through your head continuously and the emotions that reflect those thoughts. All those things make up your sense of self.
Wherever you are, be there totally. If you find your here and now intolerable and it makes you unhappy, you have three options: remove yourself from the situation, change it, or accept it totally. If you want to take responsibility for your life, you must choose one of those three options, and you must choose now. Then accept the consequences.