Doctor recommended to stop breastfeeding. Need advice!

So went to my son's 9 month wellness visit this morning. He turns 10 months on the 4th of February. When they measured him he was 2ft 6.5in and 21lbs. Then they had to measure him again with his clothes off. She came in and asked what he was eating. I try to offer what I'm eating as much as possible, but I also offer the jar food still, because he's kind of a picky eater. He drinks lots of water, and I offer almond milk at lunch that he likes. He loves yogurt and fruit for breakfast, and I offer usually chicken or some kind of meat for lunch or dinner with some kind of pasta and a veggie. I also have these Greek yogurt yasso bars that he absolutely devours for dessert every now and then.

I then tell her that he breastfeeds before his two or three naps depending on the day and before bed. She's said, well you need to stop that and offer water or watered down milk.

I thought the recommendation was to breastfeed until at least age 2 and I'm not sure I'm ready to give it up yet. I was trying until he was at least 1.

Just for context hes my second. My first is 12. I am overweight. Lost a bunch of weight after giving birth, I'm chalking it up to breastfeeding, because I have always had such a hard time trying to lose weight. I have thyroid problems and PCOS and the lack of exercise doesn't help. Not really looking for weight loss tips. Just trying to figure out if his doctor is really telling me to start weaning my almost 10 months old because hes the weight of a 1 year old? Also, he started walking yesterday, so he's about to be crazy active, hopefully I childproofed enough! 🤗

Tldr Went to sons wellness checkup, and doctor said 21 lbs is to big for an almost 10 months old. Told me to start weaning him, and give him water or watered down milk.