Have you been indulging any sin in your life? Sin grieves the Holy Spirit and when you pray while indulging in a sin, God will not hear your prayers.
If you repent of that sin though and you ask God's forgiveness, He will hear from heaven and forgive your sin because the blood of Jesus washes us and cleanses us from all sin.
Then all things become new and fresh and you can come to God in prayer without shame or guilt. You can be steadfast in your prayers again. Then you do not need to fear anymore because God is a God of great mercy. You can forget about that sin, do not dwell on it, that you gave in to it, because God has forgiven and when He forgives He also forgets! And so should you, forget about it. It is like a river that flows past you and that water that flows past you disappears into the sea of forgetfulness. Think of your transgression like that, because that is how it is with God.
Now that God has forgiven you, you can be happy again. Though things were dark, all things are new again, like the morning. Just like God's mercies are new every morning.
Be at peace. God is loving, good, kind, forgiving when you repent with a sincere, remorseful heart.
“If you would prepare your heart,
And stretch out your hands toward Him;
If iniquity were in your hand, and you put it far away,
And would not let wickedness dwell in your tents;
Then surely you could lift up your face without spot;
Yes, you could be steadfast, and not fear;
Because you would forget your misery,
And remember it as waters that have passed away,
And your life would be brighter than noonday.
Though you were dark, you would be like the morning.
And stretch out your hands toward Him;
If iniquity were in your hand, and you put it far away,
And would not let wickedness dwell in your tents;
Then surely you could lift up your face without spot;
Yes, you could be steadfast, and not fear;
Because you would forget your misery,
And remember it as waters that have passed away,
And your life would be brighter than noonday.
Though you were dark, you would be like the morning.
~Job 11:13-17