6 weeks exactly and starting progesterone

Today I’m 6 weeks exactly. My first OB appointment is January 7th. I started spotting yesterday with a red drop and now brown light spotting so I freaked out and the PA saw me today. She offered me an ultrasound but I knew I’d freak out if I wasn’t as far along as I think I am, so I said I’d wait until next week’s appointment. She did send me for labs and will call me on Monday with my HCG and Progestin levels. She started me on Progesterone just in case. What should I expect? I just want this baby to stick!