Now what is the link between the above questions? When you see your body in the mirror, you are seeing & relating yourself to this body of flesh & bones. When you try to close your eyes & try to be peaceful, you are trying not to link yourself to this body but to something inward, inside yourself, where you can find peace.
What is that inward thing that you are trying to find where you find yourself to be more peaceful? Yes, It's your Soul. In Soul, there is peace & you are trying to delve into that only, in times of closing your eyes or in meditation.
I am remembering an old English song whose two lines are here;
"Faces.......all around different faces I see,
Some are happy, some in misery.............."
On this earth there are more than 7 billion people & each one is having a unique face. In fact God has created a vast variety of human bodies (to create illusion) & it seems that these all people are different only. But if we see closely then we shall find that all the bodies are made of similar 5 nature elements (earth, air water, fire, space) & at Soul level all of us are same only. Variety of bodies is external only but on deep analysis it is not so & are the same consequence of few nature elements.
As per Bhagwat Gita, at Soul level all these people are one only as one all pervasive soul pervades through all these bodies.
"bhumir apo ’nalo vayuh
kham mano buddhir eva cha
ahankara itiyam me
bhinna prakritir astadha" (Bhagwat Gita: ChapterSeven verse 4)
"Sri Krishna said: Earth, water, fire, air, ether, mind, intelligence and false ego—all together these eight constitute My separated material energy."
"apareyam itas tv anyam
prakritim viddhi me param
yayedam dharyate jagat" (Bhagwat Gita: Chapter Sevenverse 5)
aham krtsnasya jagatah
prabhavah pralayas tatha" (Bhagwat Gita: ChapterSeven verse 6)
"Sri Krishna said: All created beings have their source in these two natures (Material & Soul Nature). Of all that is material and all that is spiritual in this world, know for certain that I am both the origin and the dissolution."
"mattah parataram nanyat
kincid asti dhananjaya
mayi sarvam idam protam
sutre mani-gana iva" (Bhagwat Gita: Chapter Sevenverse 7)
"Sri Krishna said: O Arjuna, there is no truth superior to Me. Everything rests upon Me, as pearls are strung on a thread."
Human body is made of Eight constituents of material nature. These elements are Earth, water, fire, air, ether, mind, intelligence and false ego. At death when the body perishes it is dissolved in these elements only but the Soul which is indestructible survives. So consider yourself to be indestructible, infinite, omnipresent universal Soul, as then there is no death for you & you are immortal.
Jai Shri Krishna