Hmm that speaks of connection difficulties to the pool of course but it's unusual that SOME work goes through but perhaps other does not. Have you left it running since then and if so what's the reject rate and how often are shares being accepted approximately? It can take the pool a while to show your full speed.

It might also be worth getting a ping and bandwidth measurement from speedtest.net or similar to check whether there are any connectivity problems on your line at the moment?