A few verses came to mind when I saw this, as Peter went through exactly what you are going through. I'd like to share those if I may, and a little background for them. When we are baptized into the service of the Lord with the Holy Spirit, we ask Do you love the Lord Jesus Christ? many times. So in that light, here we go.
In John we see Jesus speaking with Peter.
John 13:37 Peter said unto him, Lord, why cannot I follow thee now? I will lay down my life for thy sake.
John 13:38 Jesus answered him, Wilt thou lay down thy life for my sake? Verily, verily, I say unto three, The [bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse] shall not crow, till thou hast denied me thrice.
Here we see Peter denying him three times.
John 18:17 Then said the damsel that kept the door unto Peter, Art not thou also one of this man's disciples? He saith, I am not.
John 18:25-27 And Simon Peter stood and warmed himself. They said therefore unto him Art not thou also one of his disciples? He denied it, and said, I am not.
One of the servants of the high priest, being his kinsman whose ear Peter cut off, saith, Did not I see thee in the garden with him?
Peter then denied again: and immediately the [bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse] crew.
So after the death and resurrection of Jesus, Jesus is here speaking with Peter again.
John 21:15-17 So when they ha dined, Jesus saith unto Simon Peter, Simon, son of Jonas, lovest thou me more than these? He saith unto him, Yea, Lord; thou knowest that I love thee. He saith unto him, Feed my lambs.
He saith unto him again the second time, Simon, son of Jonas, lovest thou me? He saith unto him, Yea, Lord; thou knowest that I love thee. He saith unto him, Feed my sheep.
He saith unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said unto him, Lord, thou knowest all things; thou knowest that I love thee. Jesus saith unto him, Feed my sheep.
His past was grieving him. He had denied him three times, so Jesus asked him three times. And always brought back the same question. Do you love Jesus? This is at the heart of what you are preparing to do. Do not doubt, but be assured. Be of good courage. Scriptures tell us to "Repent and be baptized".
He says "Ye have not chosen me, but I have chosen you, and ordained you.."
John 20:27 shows Thomas who doubted Jesus had risen except he saw with his own eyes and felt the wounds!! "Then he said to Thomas, “Put your finger here, and see my hands; and put out your hand, and place it in my side. Do not disbelieve, but believe.”
James 1:15-8 If any of you lacks wisdom, let him ask God, who gives generously to all without reproach, and it will be given him. But let him ask in faith, with no doubting, for the one who doubts is like a wave of the sea that is driven and tossed by the wind. For that person must not suppose that he will receive anything from the Lord; he is a double-minded man, unstable in all his ways.
Romans 14:23 But whoever has doubts is condemned if he eats, because the eating is not from faith. For whatever does not proceed from faith is sin.
Mark 4:40 He said to them, “Why are you so afraid? Have you still no faith?”
There is a specific reason that you doubt. If I may at this time, as what is really going on in your mind? When you think about the creator of the universe speaking to you directly, does that not make you happy?
Hebrews 11:6 And without faith it is impossible to please him, for whoever would draw near to God must believe that he exists and that he rewards those who seek him.
When I went to my grandparents house, they have a swimming pool 16 x 32ft. Decent size pool. deep end, diving board, etc. I would often ask "is it cold"? And not be swimming. Gram would say to me "jump in". So jump in with both feet.
Acts 8:36 As they went along the road they came to some water; and the eunuch said, "Look! Water! What prevents me from being baptized?" You are.
What is really stopping you and causing your doubts? You are. You're letting Satan plant doubt.
Follow in the Lord's path and he will give you joy. It shall be a spring springing up from within.
The devil attempts to sway us from following the straight path. He will try like #&77 to keep you from getting baptized if you have already taken Jesus into your heart. This is doubt. Satan will plant the seed of doubt and watch it grow without doing anything more. Don't doubt what Jesus has done and what he will do. Say the name Jesus Christ and the devil will flee from you. But be of a pure heart. May the Lord help our unbelief. But we must do what he says first and foremost. That is put him first. Love God with all your mind body and soul. To repent and be baptized is following that commandment.