Thanks everyone. You've all said things I already know, but can't still mange to accept I guess.
I think, the issue is that I'm (despite a very active/assertive professional career person) immensely non-confrontational and easily backed down in personal life. And my in laws, lovely as they are a family of huge babies (think off the percentile charts), three generations almost of formula feeders, and a bunch of enormously sceptical people with regard to BF. The only exception is my steadfastly loyal and informed DH. after the weighing today DH was the only thing that stood between me and my temporary decision to move to formula because I was convinced I wasn't making enough milk. He convinced me to ring the NCT helpline and speak to a counsellor because I wasn't believing him and well, that worked.
So my in laws look down on BF, are full of stories of BF babies not thriving and all the babies there are very big, the thinnest one is 90th centile. I think I'm al,oat a bit on the edge as though he is on test of some sort.
I shouldn't care. In my profession, I research, evaluate empirical evidence from large scale and small scale studies, publish papers in peer reviewed journals and lecture groups of 300 plus students. Yet, in my personal life I'm now married to baby scales, and scared of any encounters with them, and trying hard just so I have a satisfying answer to them because they are so enormously sceptical of my feeding method.
Why should I care? Why can I not apply the same research, evidence, lecturing to them? Yup. No . Clue. Not. One.
But thanks all! He's had a feeding fest in bed this evening, all of us, DH, Ddog, I and baby upstairs snuggled around Netflix with food, water and loads of breastfeeding and now off to sleep. :-)