Puppies sure can be a lot of work!
Leave her in the crate, she'll be fine. Really!
We as humans are really great about making ourselves feel guilty, aren't we?
Perhaps set up a webcam so you can check on her during the day? I did that with my dogs, and they pretty much just sleep 98% of the time.
Perhaps find some neighbors who would be interested in doggie play dates?
My way of dealing with the guilt was to get a 2nd dog. I feel better knowing they are together.