Mine was invasive lobular as well ..... right breast ..... so we may be twins!! Mine wasn't in the nodes. Fingers crossed yours isn't - grade 2 often isn't.
Any small cushion will be fine if you aren't staying in overnight - but at home, you may find a 'narrow' cushion easier to 'support' your arm. Make sure you take your pain meds - do NOT assume you won't need them!! Sleep is essential - and if in pain, you won't sleep.
We have some wonderful WA members who may be able to point you in the right direction for services close to you ..... @"Annie C" and @JJ70 are two - with others as well. Pop your 'city' in your profile name - and others will jump on.
Make sure you take a buddy with you when you get your pathology results - it is hard to 'remember' everything they say! Or, at least record it on your phone, for later reference. It is your medical team that will suggest your later treatment. I dodged the chemo bullet, but went with Rads, due to the invasive nature of the pathology. Your medical team will advise you on this.
Once it is 'out' - you will be amazed at how much 'better' you feel! xxx take care & all the best for tomorrow xx