I'm so scared :( thyroid and pregnancy?

Hello ladies.. I'm about 5 weeks today and this morning when I wiped it was brown.. like dried blood.. should I be worried or go to the ER or something?? I don't see my dr for another two weeks and i had a MC last year in April and haven't been able to get pregnant until now.. I love this baby so much already I'm desperate.. also, I had half of my thyroid removed and haven't been on any type of medication.. I'm scared that could contribute to the reason why I would be having a mc... I know I shouldn't be this negative but I can't help if :( anyone with thyroid issues get through a pregnancy okay?