Does this sound like GER?

Hi Ladies,
I am after your advice again about my wee one.
Two days ago I noticed Ellie's breath has started to smell of sour milk when she burped and it has become worse since plus she is showing signs of tummy pains and is crying a lot now. She is 7 weeks old and BF. Do you think this is the start of GER and if so any advice on what I can do to help her. I so hate to see her in pain and upset.
Many thanks in advance
Pict