Change in symptoms?

Andrea • Baby boy born 2015, excepting babe #2 in April 2019!
Alright, I'm probably over thinking this but thought I'd post anyways. My boobs were pretty sore the past week or so and this morning when I woke up they were significantly less sore than they have been. I haven't really had any other symptoms except mood swings. So, now I'm worried something is wrong! Do symptoms change weekly? I'll be 6 weeks on Monday. Anyone else experiencing this?