7 Weeks - Lessening Symptoms (Cause?)

Hi, I’m 7 weeks, 3 days. I’ve had nausea and breast tenderness since a few days DPO. Had my HCG checked around 5 weeks and it was doubling - great levels. But since I hit 7 weeks, my nausea has subsided, and my breast tenderness is more intermittent, versus constant. I’ve read here a lot that symptoms can come and go - so that’s reassuring. But is there something significant about 7 weeks that makes this more common? I read the umbilical cord is forming, does that take over some of the hormonal regulation, lending itself to lessening symptoms?

Anyone else experience lessening, or waning symptoms in Week 7?