Help me calculate

A • Jesus is my savior.

I had my period Oct 5, I’m not due for a period until nov 2, I got a positive pregnancy Oct 25. The doc told me I’m. 3 weeks. I’m having brown discharge right now and I’m scared. Went to the doc Friday and they drew blood. My hcg is 84, they need to retest Monday. That doc said I’m more like 1-2 weeks pregnant. Help me figure out how far along I am and if this discharge is ok?