Help!

I am 6 weeks & 1 day pregnant. My dr. drew some blood for me yesterday for my thyroid & looks like my t3 & t4 levels are normal , but my TSH levels are low. Dr. Says this is normal & I don't need medication. She said as long as my t3 & t4 levels are normal, then that's all that matters during the pregnancy? Is this true? As I have had 2 missed miscarriages in the past that ended at 7 weeks. ? Scared & nervous now.