Pregnant and breastfeeding - supply drop?


I’m 12 weeks pregnant and have a 1.5 year old who still nurses every two hours on average.

From what I understand I should expect a supply drop sooner rather than later but I’m just wondering what to look out for.

The only thing I’m noticing the past few days is that she isn’t doing as many wet nappies and I think I don’t hear her swallow as much while she nurses. I’ve been trying to get her to drink more water but she doesn’t really want to drink much. (No signs of dehydration so I’m not too worried yet)

If you are/were pregnant and noticed a supply drop, what gave it away?