Appointment with plastics coming up. Not sure what happens next

For context, I turned 31 earlier this year. Diagnosed with low-grade DCIS on 7 May. It's been a long wait between the diagnosis and my next appointment on 11 June with plastics. I'm supposed to be having another MRI on 10 or 14 June (depending on when my period starts), and then the appointment with plastics. I'm not entirely sure what's going to be happening at the appointment - I'm assuming they explain the double mastectomy with lymph node biopsy process, and book me in? Has anyone had an appointment with plastics and then had to wait longer before they confirmed when your surgery was going to be?

Does anyone have any questions they wished they'd asked at their appointment? I've been advised I'm not eligible for implants, so will likely be having the DIEP flap surgery.

What worries me most is that they're going to find out the cancer is more advanced than we thought, and I'll have to have the surgery a lot sooner, or even chemo. I'm extremely fortunate at this stage that I won't be needing chemo if I have the surgery. Except, I've been having swelling and discomfort in the right breast that has been getting steadily worse since early February. It's mildly painful and rather uncomfortable, has visible swelling in a distinct area, and now creates a real dimple when I raise my arm. I'm hoping it's just something simple like extra lymph buildup after the many biopsies I've had in the last year, but I can't help but worry. I had it checked out by my GP the other day just to have my concerns noted on the record and she said the only thing she could offer is an ultrasound, which is a bit pointless when I've the MRI coming up anyway. I'm trying to focus on the things I can control right now, but any tips you have to help me getting through the next 11 days (and then probably another 7+ for the MRI results) would be wonderful.