Rohey - I've got a lot to say, but please please please don't feel lectured at, OK? - I've been where you are, and YES it's very stressful and upsetting.
First and foremost, you are NOT A BAD MUM. If you were, you wouldn't be so worried and upset.
When my ds, now 3.5y, was 8.5m he went from being an enthusiastic eater to eating virtually nothing for 5 weeks. It was hideously upsetting for all of us, especially when his ribs and hips started to show. He didn't put on any weight during that month either. Then the first teeth appeared and suddenly his appetite was making up for lost time.
So, yes, your HV could be right (which doesn't really make it any the less distressing for you).
Your dd sounds healthy and alert to me, so you really and truly do not need to worry. Even if the ribs show! Babies are resilient little creatures.
The most important thing for you to do now is not to stress about this, and not to transmit your stress to your dd. Don't try to bribe her with the sorts of foods you wouldn't want her to live on - chocolate and icecream, for example. Just offer her tiny portions of things you know she likes. And if cooking and chucking it distresses you - don't bother. If you can afford it then use jar foods. Try giving your dd something to hold during mealtimes - a teether, keys , or a spoon perhaps. How about taking your lunch or supper out into the garden?
The important thing is to come through this period without any 'hangups' that might make it harder for you or your dd during future meals.
I speak with the voice of experience . I stressed myself and ds during his hunger strike, and reaped the whirlwind over mealtimes and food 'fights' for a long time afterwards. TBH, I only really understood what was happening with ds's eating when dd started solids and I realised that she eats masses more than he ever did, even when I thought that he was an enthusiastic eater with a good appetite. When dd was 8m and ds was 3y, dd was eating two to three times as much as ds!
I finally understood that each child eats as much as he or she needs. I learned to ease off on ds (difficult, took months, and I still need to remind myself to ease off) and his appetite improved a little. Fortunately this was also the time that dd's appetite decreased, so I understood what was goinng on and didn't stress about it, just let her get on with it. Now dd is 18m, ds is 3.5y and she only eats perhaps 1.5 times as much as ds. He is still slim with visible ribs, but then she is not a chubby baby either!
Sorry for such a long posting, but I felt that my story might help you.
Chin up, you'll come through this and it will all be OK.