Hi there... there isn't any reason for you to be so depressed about your daughter's diagnosis of Graves Disease... Why don't you give me some more information and I'll try to help you work through it, so you don't feel so bad about it?
First off, do you know what her current thyroid hormone levels are? They should have tested her for Free T4 and Free T3, along with the pituitary hormone, TSH. If you'll post those results and their reference ranges, it would be most helpful.
Also, can you tell us what tests were done to diagnose Graves Disease? There should have been some antibody tests done prior to the diagnosis...
Also, what treatment is she receiving and how long has she been receiving it?
How far along is her pregnancy?
Thyroid hormones are very necessary for the growth and development of a fetus, so it will be necessary to monitor her hormone levels to make sure they don't get too low, since the fetus depends on her hormones until its own thyroid is developed enough to produce the hormones.
Many women require higher levels of thyroid hormones during pregnancy, so perhaps you shouldn't worry so much...