Alz - Check with your CHN - give them a call. Or speak to a pharmacist - their advice is free at least! I know its hard when the tin says should be drinking 120 ml per bottle but just average out how much he has in a 24 hour period. I was freaking out cause Caitlyn was only taking 60 ml some feeds and 120 the next but when I kept a record (and I recommend only doing it once!) she was averaging around 700 ml per day. I give Caitlyn S26 and it says that she should have 6 feeds at 120 ml which is 720 ml. So she is getting about what she needs and obviously Ethan is getting what he needs too if he is gaining weight steadily. Its just hard when he is obviously in discomfort. I am sure you will get lots and lots of advice about picking him up or not picking him up but in the end you have to do what you feel is right. Just remember that he can probably feel how tense/stressed you are.
When I am feeling particularly stressed about my bubby crying is walk around with her in my arms thinking how lucky I am to be holding this child and how beautiful she is. Good luck!