Brown discharge 11 weeks

From last couple of days i m having brown discharge on and off. Im 11 weeks 1 day today. I hd my appointment 2 days ago. Doctor ordered blood tests and asked me to rest and take it easy( which seems impossible with a 2 year old running around all day long without any help). Yesterday nurse called and said my hcg numbers r great. Scheduled me for vaginal ultrasound tomorrow. Just anxious if its normal because before it i had like yellowish discharge for few days which now turned into brown. I also had sex couple of days ago(spotting started after that). Now im just wondering is it some kind of infection of just normal.