@Sara7455 hope you're feeling ok? Just take it steady, not only have you had major surgery but you were unwell before that so your body needs rest. Just take your time and don't compare to others who bounced back. With my first I felt wrecked for weeks.
And yes to Lansinoh! It's magic. Your nipples will really hurt to start I found keeping them cool with a cold flannel and not having material on them to let them breath helped. Hard when you're in hospital but maybe sit in the loo for ten mins with your bra off!
Sorry to hear about the back ache. I ended up doing a 10k Walk last as was chatting with friends, my hips after were soooo sore!! Trying to keep up with Pilates is helping keep pains at bay so maybe try that? I do one on YouTube by BodyFit by Amy.
Re washing clothes. I would just do in regular detergent, then do a rinse wash after as it will take any residue off that may irritate the skin.