I'm so at loss right now my first baby was sooo easy to potty trained she like did it herself with…

I'm so at loss right now my first baby was sooo easy to potty trained she like did it herself with in the first week she was trained she was 2year old exact well my second is very very jealous of this pregnancy I'm going to have him very soon but she is saying she is the baby and she needs diapers 🙄 I tried to just let her wear just undies and explain to her she's like mom and Sissy but she just pees I live in a apt that has carpet so I can't just leave her and let her pee herself I really really didn't want to buy double diapers again I thought I wld have her potty trained by now