Thyroid risk of miscarriage

I'm freaking out. I did blood work at 4 weeks and my doctor told me today my thyroid levels are around 4. They're supposed to be below 2.5 or there's an increase of miscarriage. He called in a prescription for 50 mcg of Synthroid. Does anyone have experience with this happening while pregnant?

Please help! I'm freaking out every time I get a cramp now.