TSH very high and pregnant!

I’m 5 weeks 5 days pregnant and had a slight spotting so i went to the emergency room and everything in the ultrasound looked good! I took a TSH blood test and it came out 54!!! Im freaked out!! The dr told me to take 100 mcg Levothyroxine. Did anyone go through the same? Did anyone deliver a healthy baby with high tsh? Please help! Should i take more levothyroxine?? And how long does it take to go down?