I haven't soloed yet. Still have too much fun with combinations. But I think you mistake was leveling up too fast vis-a-vis increasing your combat skills. It could be that you character isn't a viable (solo) choice. Or you character has been developed incorrectly.
But I'm betting it's that you didn't hold off on your leveling. I think you should have been around level 5 or 6 with a ton of non-applied level up experience.
My .02$US.