I went back to work when ds was 6 months too. 2 days a week with family coming over to look after him. I was very lucky I work close to home so could go home to feed him at lunch time. I expressed before I left so ds could have his late morning feed and late afternoon feed. He always drank less than he would when I was home but make up for it in solids (we did blw). Ds wouldn't drink from a bottle but would from a sippy cup. Now he is fine to go all day without a feed, just a big feed in the morning and again when I get home.