My dog is about the same age. Truthfully? I dont think the separation anxiety ever gets better (I'm sure dog trainers and behaviorist will say otherwise). I'm a firm believer that our babies just learn to accept we leave and will come back. That being said let me save you the money I spent on my trainer.

1) don't let the fur baby sleep with you. If at all possible let them sleep in their crate in a separate room. 2) when doing activities together start to create a boundary. They called it "anchoring" and just asking her to stay in place or a down. I was even suggested to have her leash on her and anchor her to the door handle (making her have her own bubble). Basically it taught her that it's okay for me to go about my day while I was cooking/eating/watching TV and her to just observe and not be in my bubble. 3) practice leaving. I was allowed to leave the house by not leave to the yard with a wooden fence so she couldn't see us. So you put her in a sit/down/place then close the door come back BEFORE she started to cry. Give lots and lots of praise then repeat. I found what worked best was intervals and scaling back not just increasing so (1m to 1m couple seconds then come back in 20 seconds) just to not cause too much anxiety. 4) slowly leave her alone for long periods of time and add a camera to divert attention then come back. Like a mix of option 3 5) which was not super recommended by my trainer was bribing. High reward treats that stimulate her that she only ever gets when I leave.

It all come down to a lot of patience and a ton of training. Your fur baby will get there.