If your doctor has advised it then I would consider it. However I would be asking for a referral to an allergist and a paediatrician as well. I found the paediatrician and the allergist to be far more helpful and reassuring than the gp. My son had his first allergy blood test at 4 months so maybe you could get testing earlier through a specialist.

when my daughter was a baby she was sick and had an upset stomach when I gave her regular formula. so I started giving her soy formula and it worked a treat. She had that for a while and then I went back to giving her normal formula and she was fine. sometimes babies stomachs just can’t handle normal formula at the start of their life.

I haven’t used it but a friend of mine has a little one with allergies and used a prescription soy. I think she said that getting it via a prescription was a bit cheaper.

When my daughter was born (nearly 15 years ago now) i was also breastfeeding her but she kept being sick and quite ill so they thought she was milk intolerant so she was put on baby soya milk.
It smells horrible but it worked a treat she was never sick on it and put weight on just as normal, at 12 months they told me to try her on full fat milk to see how she went and all was good she kept the milk down.
Bit of advice if you do use soya milk watch out for baby sick its smells so bad and seems to hang around longer to lol
Good luck