Don't be too discouraged...she's just having to deal with the adjustment from littermates and Mom to sleeping alone...you could try wrapping an old fashioned alarm clock(that ticks) and a hot water bottle in a towel for her to sleep with...also, don't be too discouraged about the accidents...she can't really help it...they are VERY sensitive to change of any kind and that will cause her to "forget" anything she has learned as far as housebreaking...the most important advice I ever got was to remember that if the puppy had an accident, it was OUR fault, not the puppies...also, as hard as it is, NEVER take them out of their crate while they are crying...it only teaches them that crying will get them out...that leads to a ton of frustration for everyone...
Oh, and if you decide to let her sleep with you(as some people do) you might get her a doggie bed and put it on your bed with puppy pads under it in case of an accident...I don't personally like the puppy pads for "housebreaking" because they teach them it is ok to go in the house sometimes...it can be confusing...there needs to be a consistant potty spot outside...but, to protect your bed in the night is different...I personally let Mic sleep with me when he was tiny...but, we ended up getting a second boxer(his brother, same litter) and then they slept together in their crate and we've never had a problem since! So, that is the limit of my experience...I know there are TONS of folks here with just one who can give you more ideas...
Hang in there! :wink: