Milk protein allergy? Constipation?

Hi! So my baby is 11 months old and has a milk protein allergy. I’ve recently tried giving her a little lactaid just to see how she did with it. I gave it to her Tuesday and today is Friday. It made her super gassy, which idk if that would mean she can’t handle it, but also just now she had a tiny bit of blood in her stool. Lately she poops once a day but her poop is ALWAYS tiny hard balls no matter what I do! Prunes, prune juice etc.

Im a little confused. Should I assume it’s from her milk protein allergy and she cannot handle lactaid. OR I’ve heard of blood being present due to constipation. If it’s tiny balls and she goes every day could it just be blood from contipation? She has her 1 year appt very soon, just curious what you guys think.

Thanks!!