Girls, who had thyroid problems during pregnancy? I saw an endocrinol…

Girls, who had thyroid problems during pregnancy? I saw an endocrinologist today (at 12-13 weeks), the doctor said that my TSH is 5.5 and this is very high. In the previous two pregnancies it was no more than 3. She prescribed Euthyrox for now 25 mcg. I'm very worried. After 6 weeks she said to have a hormone test done. Will this TSH go down?