Thyroid and pregnancy

Any ladies out there dealing with hypothyroidism while pregnant? I'm about 9 weeks... was diagnosed as subclinical several years ago and never did anything about it (bad, I know) but now that I'm pregnant and my tests show elevated TSH levels they are putting me on some hormones. I have to admit I'm a little freaked out. They want me to get a thyroid ultrasound as well... Anyone else start thyroid meds while pregnant and have a good/bad experience?