Backstory to avoid drip feeding:
My original intention was to exclusively breastfeed DS but he has been combination fed from day 3. He was born by emergency c-section following a long labour. The induction drip caused us both to have low sodium which left both of us excessively tired for the first few days. This combined with tongue tie meant the feeding got off to a poor start. As he hadn't pooed in the first couple of days, the hospital told us to start topping up with formula after every breastfeed, which we did. He had a tongue tie op in hospital when he was three days only (I assume for the forward tongue tie). He was gaining weight okay but only when we continued supplementing with formula, otherwise he would stop gaining weight. Other than the weight he always seemed fine - he's always been a happy little baby who's pretty alert and seems to be developing with how the baby books suggest he should.
I still felt something wasn't quite right with his latch as he never stuck his tongue forward and the GP said we had a weak suck reflex, so I took him to a private lactation consultant. She said he had a set back jaw, retracted tongue and posterior tongue tie. The did some osteopathy to bring his jaw forward and corrected the tongue tie with a second operation the following week (in week 6 of his life). After this his suck improved a lot. Gradually he started drinking less and less formula, and bottles were continually going untouched, so I thought 'Yey, finally my supply is catching up' and now we only offer him one bottle a day (in the evening) which he barely touches most nights.
But just got him weighed again today (week 13) and he's lost a little weight since he was last weighed three weeks ago. HV said we should go back to supplementing with formula after every feed, which of course I will, though I'm worried about whether he'll take it. I just feel so disheartened by it as I really thought we were making good progress and now it just feels like we are back to square one! Also I don't understand why he wasn't drinking much of the evening bottle we offered, as surely he would it he were hungry? But obviously not! Part of me feels like it would just be easier to switch to formula full time as at least I'd know exactly how much he was drinking, but I don't really want to do that. I'm dreading starting solids as I've heard that babies loss weight initially on that too.
Has anyone got any words of comfort / advice? Particularly if you were in a similar situation.