I hope this isn't too offensive but it's not the sniper class that is the problem it's you. You had it easymode when you had a healer companion for your first companion and now you think the rest of the game should be that easy. It isn't, but it's not impossibly difficult either. I did just fine until I finally got Dr. Lokin(our viable healer companion) in my lat 30's. Now it's Bounty Hunter style easymode for me too. Don't bother gearing up your RV 48 by the way, he doesn't heal for crap.
Now for some constructive ideas for you;
A:Learn which abilities do what.
B:Gear Kaliyo up, at leat until you get Dr. Lokin in your late 30's.
C:Undertsand your limitaions, be prepared to rest in between fights.
D:Practice makes perfect as they say, but if you just can't get the hang of it reroll. You don't have to level your sniper.
Good luck!