Hi
MissJ don't worry, you can't reduce your milk supply by expressing. Either putting Nye to the breast more frequently or expressing after/between feeds is the way to encourage your body to make more milk.
An empty breast is your body's signal to produce more. I would feed both sides in the morning as normal if thats what Nye needs, then you could either start by expressing whatever is left on the second side or if there's not much there, wait till about half way between normal feed times and express then. You might not get much the first few times, but if you do this consistently for a couple of days your milk supply will adjust and produce more.
So really its like you need to decide when you would like to express every day and sort of request milk from your body at that time every day for a few days until it gets the message.
Its really down to personal choice if you would like to top-up with formula. I know it works well for some people and can help you get a break if you don't feel happy with expressing. All that will happen is that your body will adjust to not make milk for that last feed, the same as if you are giving a bottle of EBM at that time.
Now we are getting into a better routine (if you can call it that), we give Elizabeth a 5oz bottle of EBM at 10/10.30 pm and I have to admit, I get a much more comfortable nights sleep now that I'm 'empty' when I go to bed. She was going 6 hours after a 4oz bottle up until about a week and a half ago, but then she started waking after 4 hours again so we upped it slowly to 5oz and she is back to sleeping 5 and half to 6.
Elizabeth doesn't do the headbutting thing, she bites - hard! If she thinks there is not enough there she just clamps down really hard and occasionally twists as well! I was told that babies will often clamp down to slow down a fast flow, but she only does it near the end of feeds, if the flow is too fast she just glugs and chokes but refuses to let go! She is also a pincher! She uses her little hands like a kitten or puppy to sort of massage as she feeds and her nails are sooo sharp but not long enough to trim yet. I have taken to giving her my finger or a bit of my top to hold instead as I was getting covered in scratches!
Ray Elizabeth only takes one side as well, so did both my boys. She is nearly always done within 15 minutes as well, with the majority of feeds being down to 10 now. She has finally started going 3 hourly in the day since we got organised in the mornings for the school run and I stopped letting her sleep late through her second feed time. (I am missing my extra doze in the morning though. Now I just seem to get up start going and not stop for hours on end.)