Twins 2 year sleep regression HELP!!!!

I am desperate! We used the taking Cara babies sleep training method for our twin girls at about 11 months and it worked like a charm! Well now we are at 26 months and one of the girls is going through what I am assuming is the 2 year sleep regression. I am also 8 weeks pregnant so I am beyond exhausted along with one of them not sleeping I am at my wits end! She refuses to go to bed. We are pretty strict on our schedule and we do a nap from 12-2:30 (max) and they go to bed 7:30 pm and are awake by 7:30 am. But lately the last week and half she has been screaming and crying out for us saying she’s not ready and/or she wants out of her crib. This goes on for hours. I got to the point where I messaged our pediatrician and he recommended doing 2 ml of Benadryl 30- an hour before bed just to get over the hump. It does help but I don’t want to keep using that. I’d like for her to fall asleep like she used to. It’s hard to not take her out of the room due to her sister trying to fall asleep. But then that creates a horrible habit because then every night she starts to point to the living room and wants to go in there.

Is there ANYTHING I can do?! Help me please

Thank you.