I had similar issues with a little baby that thought boobs were for sleeping on. I ended up expressing and bottle-feeding most feeds for the first few weeks until he got a bit stronger, with some attached feeds so that he still knew how to!
And wet flannels, drops of cold water, nudie-baby, bad singing were all involved too.
Do you have a follow-up appointment with your hospital or MCHN soon - it may be worth bringing that forward so they can check up on your feeding now that you have milk.