"My Lord and My God"

Thomas answered and said to him, My Lord and my God.

People often point to that verse as a "Jesus is God" proof,
 but ignore two other passages in the same chapter that do not agree with what they think Thomas meant. 

Let’s examine in context three key verses in the same chapter.

20:17 Jesus *said to her, “Stop clinging to Me, for I have not yet ascended to the Father; but go to My brethren and say to them:
‘I ascend to My Father and your Father, and My God and your God’

20:28 And Thomas answered and said to him, My Lord and my God.

20:31  <John>  but these have been written  that you may believe that Jesus is the Christ, the Son of God.

These are FOUR possible meanings.

1.  Thomas calling Jesus Lord ( a master, of authority) and God , <theos/ eloheim.  A word also applied to men, judges and kings) 

2.  As an exclamation, MY LORD AND MY GOD! -as an expression of shock and surprise to GOD above, as people do.

3. Calling him LORD (Yhwh)  and GOD (The Almighty)

4. Jesus responded to Thomas: John 20:29  Jesus said to him, Thomas, because you have seen me, you believed: blessed are they that have not seen, and yet have believed.

Believed what? That he was God? 
Or that God raised him from the dead?
The context of the conversation is the resurrection of Christ, and not deity

There's only one answer and it was the fact that God raised him from the dead.
Reading a few verses prior should help us understand the best choice.

John 20:17 (NASB) Jesus *said to her, "Stop clinging to Me, for I have not yet ascended to the Father; but go to My brethren and say, 
'I ascend to My Father and your Father, and My God and your God.'"

Because the word “God” or “theos” are not exclusive terms for the Almighty. 

It may refer to anything likened unto God, Gods Representative, or one entrusted with the word of God, a judge, a ruler, or king. All of which apply to Jesus.

Jesus said the Father is the ONLY true God and he said the Father is "MY God".
John said exactly why he wrote in John 20:31(NASB)

but these have been written so that you may believe that Jesus is the Christ, the Son of God; 
and that believing you may have life in His name.

Summary:
How many times did anyone say or preach  “Jesus IS GOD”?  -0.
How many times did anyone say or preach Jesus is the “SON of God?  42 Times (NASB)
What are we to believe? -"Jesus is God" or "Jesus is the CHRIST, the SON of GOD"?
-and that God raised him from the dead, which is what Thomas came to believe.

..................................................

Does Thomas' exclamation  PROVE JESUS is GOD?

While GOD Almighty was still on the throne?

Did Thomas know that Jesus had just said "....I ascend TO MY GOD AND YOUR GOD" and somehow think Jesus was God?

DID JOHN knowingly write that Jesus was ascending "TO MY GOD AND YOU GOD"

and yet John still finished his gospel with "these are written that you might believe that Jesus is the CHRIST, the SON OF THE LIVING GOD"?

And WHY did NONE of the preachers in Acts say "Jesus is our GOD" or a simple "JESUS IS GOD"

***IF*** it was so?

These are clear reasons to think about and stop trying to prove what no scripture says:
 i.e. "Jesus is God".

He that overcomes is he that believes Jesus **IS** the Christ, the Son of God".