You know - you don't need to see a HV. You can stop going and just enjoy your baby.
I'd have killed for an average of 3.5+oz a week average weight gain - yet my baby is is now a healthy 7 year old, on the 50th centile for both height and weight (I've only just bothered going and checking, after probably about a year or more). He was never a "Failire to Thrive" baby - although some ignorant HVs might have categorised him as such, looking at his growth charts (born 91st, big inital drop, 7 weeks to regain birthweight, dropped through the growth curves till started follwoing a line just underneath the bottom one, eventually started creeping up and then followed the 25th, before eventually creeping up to to the 50th, where he has remained). Happy, healthy and alert throughout - barring a short period of sleepiness early on, due to neo-natal jaundice.
Reember centiles are averages - as jellybelly pointed out on this thread www.mumsnet.com/Talk/1364/383944?stamp=070919095758 (which you should look at to give you strength)
"And anyway if your baby is healthy and developing normally it really doesn't matter. The whole point of an 'average' or a 'centile' is that it represents a huge range. It is mathematically impossible for everyone to be 'average' and I don't know why so many HVs Drs etc think everyone should strive for it. Makes them feel as though they are doing something constructive I guess.
(I have a long waffle prepared about how if all efforts to get low weight babies to increase their weight worked then the magical averages/centiles just increase anyway, hence the next batch of babies have a higher average to reach and people perpetually get fatter and fatter and fatter.... But I won't go into that, lol )"
Your baby is fine. Not just fine - your baby is doing brilliantly - and so are you
STOP GOING TO GET HER WEIGHED.
Start just enjoying this time with her - they are only this wee for such a short time. You are doing a great job.