Stressed! Unexplained pink/brown/bright red spotting

Ha

I'm 23 weeks pregnant. I've started spotting since week 20. I've noticed the spotting occurs only in the morning after I wake up. Mostly when I wipe. The spotting is usually light pink, brown, and 2-3 times bright red. Each time, I see bright red, I ringed my OBGYN. He checked my cervix and baby. Cervix is closed, but he did mention the cervix is getting shorter gradually. I went from a 4.1cm to 3.5 now I'm at a 2.7cm. Baby is healthy and fine. My AFI is on the low normal, but it shouldn't be a concern. He couldn't pinpoint the reason to why I'm spotting. I've visited him multiple times now for this issue. I'm still spotting and I'm so overwhelmed. My doctor put me on bedrest with progesterone suppository rectal insertion 2 (400mg) times a day. It's been three weeks, and I see no improvements. The bedrest is also driving me crazy but I know it's best for my baby. I just don't know what to do. I hate the feeling of knowing my cervix is getting shorter and anything could happen in the upcoming weeks. My mind is always wrapped around having an extremely preterm baby, so I'm constantly searching for ways to remedy my cervix situation. I brought up to my Obgyn that I want a cerclage, but he said we can't do that procedure when you're spotting. It drives me insane. Anyone had experience with unexplained spotting for a long amount of time, weakened cervix, low normal AFI, and baby turned out fine?

Please, I need to some stories, to know I'm not alone. I'm so sad