Wah How to use "Was / Were + going to"

Was / Were + going to is sometimes called "the future in the past."
It's often used to express disappointment or anger.

• You told me they were going to play my favorite song!
• I thought Wah Wasabi's website was going to be interesting, but it's really boring!
• I thought you were going to help me.
• He told me this examination was going to be easy.
• You told me it was going to be ready on Friday.

As the song "I Was Gonna Marry You" by Tristan Prettyman:
"I don’t even know the truth.  Yeah we were fine, yeah we were fine.
Then all at once you changed your mind and I was gonna marry you.."

Note: I was gonna marry you or I was going to marry you.