Im like this most of the time, for me its just being patient until a new idea crops up. Their are some different ways to help spark your creativity though, for example, why not try experimenting with different tunings? Mark Tremonti is a big proponent of this and i find it helps to make some fun and interesting riffs and chords progressions. If not this then why not try finding some drum beats on youtube and playing along to these? I've had quite a lot of success with this as it forces you to come up with something to someone else's idea, similar to if you was in a band sitution and if all else fails, i just write anyway. Sometimes you just need to get rid of some of the rubbish ideas to make way for the good ideas in the back of your brain but sometimes you'll surprise yourself and make a good song out of the riff or chord progression you originally thought was no good.
Hope this helps.