I really feel you on this, it is so stressful when your baby just refuses to drink no matter what you try. Since it has been going on for two months now and she is rejecting both FM and BM, I think it would be good to bring her to see the PD just to be safe, so they can check her weight gain and rule out anything like reflux or oral issues. Starting purees is fine at 6 months but the PD can also advise whether the solids timing might be affecting her appetite for milk. You are doing a great job trying everything for her, hang in there.