Pregnant 7 Months PP and Losing Supply

I found out I am pregnant earlier this week, since then I had my HCG bloodwork done 48 hours apart. My HCG triple in the 48 hours and I've noticed a massive drop in my supply. My son didn't have a wet diaper overnight usual and didn't have quite as many as normal yesterday, not a huge a difference but noticeable. I used to have a massive let down that I felt and now it rarely comes. I think I might have to start supplimenting formula. I'm so disappointed in myself and am regreting this pregnancy. I love nursing my son, he loves nursing, I'm not ready to stop but because the drop is due to hormones I dont know what I can do to get it back. Anyone else go through this and were able to reverse it?