Fluctuations in breast size and tenderness

The past two days my breasts have been less tender and not as full as the previous week (during which I had to purchase a larger cup size bra to accomodate the swelling), and today they're tender but definitely smaller than last week.  Still larger than before BFP but it's still freaking me out.  Is it normal for size and sensititvity to flucuate?  I had a miscarriage last year and prior to my symptoms disappeared - so I'm hypervigilant.