Hyperthyroidism and pregnancy

I don't have my first ob appointment for another 7 weeks, but I've known I've had hyperthyroidism for a few months. And I'm concerned how my hyperthyroidism will affect the baby I'm 5 weeks and 2 days, when I scheduled my appointment they told me to discontinue using my meds cause they weren't pregnancy safe. Anyone else have hyperthyroidism ?? My sister has graves disease, and she had heart palpitations and high blood pressure, and had to have an emergency c section cause she had a thyroid storm. But graves disease is much more severe than regular hyperthyroidism.