Did you do all the missions on Belsavis. If not they might still be green for you so they would still yield some XP and you could run through all the quests there and hopefully get yourself another level or two. Otherwise you're probably stuck doing PVP, flashpoints, and space mission dailies like you said

Having the same issue. Really hoping BW fixes it soon since I'm having a blast playing the rest of the game and would love to get in more PVP but I just get really frustrated after 2 or 3 matches due to the lag

Madison here! GO PACK GO!