Have you had a look at any websites giving advice on Mindfulness relaxation exercises? There is a very good one run by a former Buddhist monk, but I'd better not name it as that might amount to advertising. You can learn the basics and access some simple exercise routines without having to pay anything.
I was diagnosed three weeks ago with invasive ductal cancer grade 3. My lumpectomy is set for Tue 24 Apr. I have found that simple Minfulness exercises help; you could use straightforward yoga relaxation techniques too.
You lie flat in a comfortable position (I do this in or on the bed), with your hands by your side or resting gently on your upper abdomen, then mentally scan your body starting from one toe, up your leg, up and down one arm, across your chest, up and down the other arm, then down the other leg, concentrating on how that part of your body feels against the bed as you go. Then you concentrate on identifying all the sounds around you, including clocks ticking, cats purring, traffic outside, then scan your body again, but this time concentrating on how each part of your body feels on the inside, relaxing each part as you go. By the time you've finished, you are completely relaxed and calm. All the time you are doing this, you keep your breathing shallow and in your upper abdomen. (I find it helps to have my hands loosely placed there, fingers touching, with elbows out at the side.)
Returning to a consciousness of your breathing, and keeping that gentle and shallow, is the essence of this technique and has a wonderfully calming effect. I've taught myself very quick body scans and breathing routines I can do sitting on a bus, when I'm getting panicky.
I do hope that helps.
