Brown discharge

Not really sure how far along I am. First day of last AF Dec 19th, putting me at 10 weeks today. But nurse that checked my HCG said probably 4-6 weeks. First ultrasound tomorrow and I’m nervous as crap! Since this our rainbow baby after a MC Dec 2016. Had sex with hubby last night, this morning I had a panty liner in to catch the rest of semen (SPRRY TMI) 😅 and it was light brown/discharge. No cramps or heavy bright bleeding. Normal after sex?