Welcome
@Georgesmum and your little one.
Having just (well a couple of weeks ago), got a second pup, we are going through the same with Honey.
We decided to set up an area downstairs lounge for her including the crate. This was so that Vanilla could have the main lounge and not interrupt her routine. Oh boy did we get that wrong. OH was at home for over a week and a bit, then went back just for a couple of hours for the first week. I can WFH at times to assist.
But boy did she shout, scream, bark, howl and whatever else the house and neighbourhood down. I could hear her as I was walking up the road. This was even after doing some training with her in being in the crate and play area. We had a baby gate across the hall to allow Honey to get more area.
Nope that would not work. We could not have her be so hysterical, where I would say it was like someone having a panic attack. Because we had to get her settles before we both went back to work, even with a dog sitter coming in to assist throughout the day.
We figured we would move the crate and set up the play pen within the larger lounge to be nearer Vanilla. I decided to spend time with her within the pen to try and settle her, she would play within the pen, would lay down and let her fall asleep. Once asleep, I would leave and that worked until she woke up. Would leave her crying for a few minutes, then come back once she was quiet. All this worked for a short period, but because Vanilla has the whole house when she disappeared all hell broke loose again. As much as when I got home one day the pen had become so small, due to her moving whilst trying to get out.
So we ended up with option 3. Honey got the lounge downstairs and Vanilla gets the remainder of the house. Baby gate between them and now when we leave Honey is OK and happy with her Kong chewing on it for about 30min, even though all the food is gone within about 5min. If she hears Vanilla upstairs, she will give a small cry for about 30sec. but then fall asleep. One thing we do do is if we need to leave through the front door (rather than garage), we open the door and leave slightly open. It makes a minor noise when opening, but I can control the noise when closing (just not opening).
Of course now we have a different issue which I will post separately.
What I am trying to say is you will get there it just takes time. I never thought it would be this difficult to settle Honey, given when we got Vanilla she was settled within a few days. They just need to know that you are coming back, which once they realise that you are, they are happy.
if I’d have realised this before trust me I’d have thought twice about the whole thing 
)
). And we have all been there, done that, got the ripped T-shirt etc.