today is my day!!!!

Last night, I couldn't sleep，because that i feel I was under a lot of
pressure for my Certification and License exam.

Today,
God loves me!! I pass passed the exam. I feel vvvvvvvery happy!!!
I am excited-------->exciting? or excited????

*excited is CORRECT.
*exciting is to describe something which made you feel excited.  

Today is my day!!!!

Last night, I couldn't sleep because that i felt a lot of
pressure for my Certification and License exam.

This sentence is strangely worded.  A better (and much easier) way to express this idea would be to say "I was nervous about my Certification and License exam."

It is also unusual to put a comma before the word because.

today,

God loves me!! I passed the exam.  I'm vvvvvvvery happy!!!

Be sure to include a verb in your sentence.  I *am* very happy.  This is different than Mandarin and is a very common mistake to make.  Adjectives still need is/am (是) in English.

I am excited