I know what you mean, been there too, it can be kinda frustrating not being able to decide what to play. I have a level 71 and 4 alts between level 7-12, I cant tell you how to handle it exactly, because every person is different.
All i can say is: Play what you feel, you want to be playing.
I was stuck in the same level range is you describe you are, for me it helped taking a break and do something else, one day after I logged on my Guardian and now he’s level 71 and going fast towards 80.
Just take it slow, switch between them, play them all, sooner or later you will figure out how to handle it.