Takin correct type. Is it normal 20 years after DS to have worse problem with absorption? Can't think of any dietary or medical changes to all of a sudden have trouble maintaining my low but acceptable levels of calcium and protein.

I had DS in 2002. Have faithfully taken supplements. Maintained levels until this year. Take 3600 liquid calcium over day plus wear 3600 patches at night but is still to low. Don't know what chnged. Anyone able to help me?