Nipples got lighter!?

I am 5 weeks 2 days and don’t have very many symptoms (no morning sickness, a little bit of frequent urination, on and off sore breasts and nipples). The last couple of days I noticed my nipples had enlarged and my nipples got a little darker. This morning I noticed my nipples got light again. Has anyone had that? I worry about disappearance of symptoms because I’ve had two miscarriages around 5 weeks. I am still taking pregnancy tests every now and then and my lines are very dark (much darker than control). I worry about MC because I’m taking progesterone, which could mask bleeding symptoms. Let me know if you’ve ran into this!