My husband and I have a pup, who shows real signs of separation anxiety. Every single day she urinates and defecates in her crate, without fail. Is there anything I can do differently?

My husband and I have a 14 week old black lab named Marla. She has been with us for 6 weeks. She shows real signs of separation anxiety and appears to be a clingy puppy. She doesn't like to be left alone and when she is out of her crate she follows me and my husband everywhere we go. During the day we put her in her crate while we work, which has been reduced in size so that she just fits and can just stand and move to lay down. Every single day she urinates and defecates in her crate, without fail. It appears as though she is doing it multiple times. I have done things to try to alleviate her anxiety, such as giving her a kong toy and putting a tiny bit of cheese or treats in it just before I leave the house (the only time she gets that toy is when I put her in her crate for the day). This does alleviate her anxiety when I leave the house, as she no longer cries or panics. However, she is still eliminating in her crate. When we are home with her at night and on the weekends she does not alleviate in the house. She will walk over to the door and sit down and wait for us to let her out. Is there anything I can do differently? Is her bladder / bowels just not developed enough yet? I do not punish her when I come home and she has gone in her crate, but my frustration is growing, as every day I come home to a smelly house and must take half an hour or more to clean her crate. Any suggestions or advice would be greatly appreciated.

Thank you,
Tara