Excessively worrying about my nearly 10 year old DD

For context, I am pregnant wiith my second childwhich may the reason for such heightened feeling, however, I am unsure, that this is just hormones alone.

My daughter, very recently has begun to show the first signs of puberty. Little breast buds, and then 6 or so weeks later, very fine pubic and underarm hair - barely notiable, it just looks like leg hair so not sure if it counts as pubes, but there's def some big changes going on. SHe is also getting heavy discharge more or less everyday and compains of rando tummy cramps.

She is tiny, only 4ft4, weights 4st2 (60 pounds) and super slim. It's a struggle to get her to eat much at all.

I took her to GP yesterday for a suspected urine infection who told me to get ready as her periods could be starting imminently!

I am SUPER worried about her period being round the corner? Could this be the case? The GP says it isnt unsual. But she is so small still. I've read that at most girls only grow 4 more inches after their period starts, meaning she would only be 4ft8 in adult height. I am 5ft6, my partner 5ft8. Whilst she is never going to be tall, I hoped for her to reach at least 5ft so she can but adult clothes etc.

I also spoke to a private paediatric endrocrinlogist who advised bringing her in to check she is not going through precocious puberty and confirmed that girls tend to only grow a max. of 10cm after menarche,

I was hoping he would tell me I was worrying unnecessarily!

I also dont want to cause her to worry or think there is an issue by taking her to see him if there isnt!

Not just ths, I worry for her general health if she starts so early and is not properly nourished and her growth is stunted.

As well as all this worry, I am deeply sad to see her grow up as I am so worried for her teen years, I know these are inevitable but I assumed we had at least a couple years left of her being a little girl before these horrendous hormones and changes kick in. I have not shown her my sadness or worry, I keep it all in. But I am struggling big time.

If anyone has any advice or experiences to share, I would be very appreciative. She will be ten at the end of March. My only daughter as I am pregnant with a boy next which also brings a whole load of worries, but she is forefront at the moment!

Thanks again :-)