I would use the large wood-chippings instead of sawdust, also with bedding...try not to use the 'fur' type - use the stranded material type instead as there is much lesser dust particles. Another tip is always wash your hands BEFORE handling hamsters as they can be prone to the slightest of infections from humans. one of our hamsters (last november) had 'wet-tail' and we thought it was the runs...luckily after a visit to the vets and some medication he made a full recovery as it was caught just in time.
Having kept various types of hamsters over the last 15 years...the symptoms you explain are NOT uncommon.
Firstly...you say the hamster wakes up in the day? Well MY hamster which is a Roborovski (
http://www.petwebsite.com/hamsters/r...i_hamsters.htm) is quite the OPPOSITE to most hamsters. He actually SLEEPS at night and comes out most of the day...why? because where he is kept - which is the hall, it is quite dark even during the day so he has no real sense of time so he comes out early morning around 6.00am until around 3.00pm in the afternoon. Not ALL animals of that species are actually 'nocturnal' as most people think.
Rubbing against the sides of the cage IS quite normal on occasions and...they even roll on their backs as well...BUT not constantly. If you have other pets such as dogs etc...it could be a flea or mite infection. The thing that is worrying is when you say the hamster 'crawls' with it's tail up...THIS could BE the start of 'wet tail' which could be fatal for a hamster. The crawling could be pain of which he/she cannot walk properly so I would definately keep an eye underneath and check her discharges every few hours. If there is ANY signs of what looks like dihorreah...then it is more than likely 'wet-tail' and it needs to be acted on URGENTLY and taken to a vet. If wet-tail IS caught at the very earliest stages...then they normally recover if they are young...but please...constantly check underneath the hamster and check to see if it does solid discharges...if they ARE solid and there is NO wetness around there...then it is NOT wet-tail...if at all there IS dark and wet dampness...then act immediately.