Try and get a party going and fight something tougher? Shout in town to buy a better weapon?
The game was meant to be played in a group, but allows you some freedom to do stuff solo. So yeah, you won't get awesome-excellent XP on solo grinding. Same with Guildleves. They eventually start to step up, and become a bit more challenging. You'll get away by doing some stuff on your lonesome, but it's best to try to get a group mentality going on, and go out into the field with friends or LS mates.