vitex and BFP. advice needed! please!

I've been taking vitex for the last 2 cycles to make me ovulate and got a BFP this morning. Af is due in 2 days. I've been following the directions on the bottle that say to take 800mg for the first 8-12 weeks, then step down to 400mg daily. I was planning on stepping down to the 400mg after af arrived and I started a new cycle. But then I got my BFP this morning. I also know that if I stop taking the vitex, you can miscarry from your progesterone dropping off. My temps had been dropping for the last 2 days so I thought af was coming. Then today it only dropped slightly which prompted me to take a test and it came up positive. I don't know if I should drop down to the 400 mg, or not change anything. What should I do? I don't have a dr yet since I was waiting until my BFP to come before getting one since I just got insurance. Has anyone been in this position and has any advice to offer?