What is the misery of that estate whereinto man fell?

Answer

All mankind by their fall lost communion with God (), are under his wrath and curse (; ), and so made liable to all miseries in this life, to death itself, and to the pains of hell for ever (; ; ).

Read the 6 proof texts (KJV)

Genesis 3:8,10,24: ⁸And they heard the voice of the LORD God walking in the garden in the cool of the day: and Adam and his wife hid themselves from the presence of the LORD God amongst the trees of the garden. ¹⁰And he said, I heard thy voice in the garden, and I was afraid, because I [was] naked; and I hid myself. ²⁴So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.
Ephesians 2:2-3: ²Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience: ³Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others.
Galatians 3:10: For as many as are of the works of the law are under the curse: for it is written, Cursed [is] every one that continueth not in all things which are written in the book of the law to do them.
Lamentations 3:39: Wherefore doth a living man complain, a man for the punishment of his sins?
Romans 6:23: For the wages of sin [is] death; but the gift of God [is] eternal life through Jesus Christ our Lord.
Matthew 25:41,46: ⁴¹Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: ⁴⁶And these shall go away into everlasting punishment: but the righteous into life eternal.