GERD in 3 months old baby

Dear doctors:

My 3 months old son was diagnosed with GERD by a pediatrician. She prescribed him Zantac. I don't wanna use it and really want to try to treat his problem naturally.

His symptoms are:

-crying and fighting during and after feedings, moving his legs up and down, arching his back, turns and tosses while at the breast,

-extreme fussiness during the day, he looks like he's in pain

-wants to be held all day long

-very short and rare naps during the day, 15 min even though he looks very tired

-crying when lying on his back or lying by himself

-wants freaking feedings, like every hour

-puts fingers in his mouse all the time

He's exclusively on breastfeeding, and pooping 2-3 times a day. My boy is 3 months and one week, 60cm and 6700kg.

Would you recommend to try Nat Phos6X? If yes, what doses? He's a very bad sleeper, will this remedity get it worse?

Thank you very much for any help!