@SummerBummers Your pup is beautiful.
Im not sure I can offer any advice others haven’t but my pup is nearly 16 weeks too and seems to be ok being left alone (so far🤞🏻)
Things I have done is left her from the very beginning, just 10 mins while I sat outside and listened to her and I built it up to a hour and a half. Building up the time slowly when I knew she started being ok for the 10/15/20 mins etc.
She goes in her crate & I Never made a real fuss when I returned. Just opened the door, said Hi, smooth and took her out back for a wee.
Her Crate has a cover over.
She has a Snuggle Puppy with a heartbeat in her crate and I put it on every time I leave or go to bed.
Shes not allowed upstairs so very frequently she sees me/everyone else go up the stairs and has to wait downstairs by herself. She used to whine a little bit but now either sits and waits at the bottom of the stairs or she goes back into the front room and lays down until I/we come back.
I’d probably just let her cry for 20 mins. There will be loads of other times that you will need to leave her so it’s essential she gets used to it somehow.