7 month old on Prevacid for Acid Reflux

At two weeks old, my child started getting very agitated compared to his first week in the world.   He started screaming for 10-12 hours solid.   He had all the symptoms of colic but the doctor said it isn't normal for a baby to cry that long, non-stop, even with colic so they asked more questions.   It was determined that he was also dealing with Acid Reflux, which both me (the mom) and my husband (his father) struggle with.   It was so bad that the first two medicines did not help.   He started taking acid reflux meds around 1 month of age and is now 7 months old.   Prevacid was what seemed to make the difference.   He has now been on that since 3 months of age.   I have tried to ween him off of it when running out of the prescription the last 4 times (only get 15 pills per prescription) and after he is off of it completely, the problems start up again.   He fights eating, gets very fussy, wakes up at all hours during the night, arches his back and screams, spits up and then chokes and cries... not a happy baby (And he is usually a very good and smiley baby otherwise).   So... I keep up with the Prevacid.  

Yesterday, my mother asked me if he is still on meds and I told her yes.   She freaked out.   She feels no baby should be on prescription medicine, that it isn't normal and that it will cause him permanent damage.   I have researched it and the pro's definitely outweigh the con's.   Plus I have tried everything that I have been told to try (from the doc and other parents) as well as from what I have researched.   Natural remedies were not strong enough to do the job.   Adding rice to his milk helped a little but not enough.   Just in case it was an allergy, I tried cutting out dairy completely (from my diet as well as from formula's since I both breast feed and supplement with formula).   I also tried cutting out protein and iron.    He seemed to do worse when on breast milk alone but I was not willing to give up breastfeeding him because of how much babies benefit so we supplemented with formula at bedtime.   It finally got a little better once he grew out of the harsh months (month 1-3).   Now that he is old enough to lay on his belly, he sleeps for 3+ hours at a time instead of 30-45 minutes.   Let me tell you, I was beyond exhausted.   I still am but it is getting better.   When he has been taking Prevacid, I only have to get up with him 2-3 times during the night, verses 5-7 times without the meds.   Also, he starts coughing, seems as if in pain when coughing and refuses to eat or lay on his back when off the meds.  

So... I am at a loss, or so I believe that is the case.   It seems to me that he needs to stay on the Prevacid.   However, I have also read that it is unusual for a baby to continue use for months and months like this.   I get mixed reports.   Some say there seems to be no issues.   Some say it can cause liver damage.   Does anyone have input on longterm use of Prevacid for a child younger than 1 yr of age?   Or have any other suggestions for me to try?

Thanks!