I am constantly overleveled, even though I have skipped heroic quests pretty consistently and have been pretty uneven about hitting flashpoints.
Next planet I probably need to just stick to class quests and move on to get back to a reasonable level, especially since I am starting to get high enough to be useful in PVP once they give us a non-50 bracket.
Being behind has not yet hurt my money supply either-just go my speeder without any special effort and a fair amount of cash left over.
To the OP, this game tends not to give breadcrumb quests everywhere. Exploration is suggested. Also, think about doing PVP, grinding flashpoints, or taking a couple of days and gathering while building up rested exp while doing space missions to help you catch back up.