I almost exclusively use Doc. Once I had his healing with me on missions it was almost like easy mode was turned on. http://www.torhead.com/npc/huZUf96/doc Edit: You get him on Balmora fyi.

Level 47 Sentinel here. Watchman is fantastic. I have yet to find any real problem leveling with it. The burns ignore armor and once you understand how to properly combine the stacks with Zen timing you can watch elites simply melt before you. Additionally things like 2 points in force camouflage talent, which gives 100% damage reduction and dumps threat, is a great way to dump aggro to your companion for a minute to get your health back up. I would suggest using Maefly's guide for a good spec and rotation explanation as well as OS theory craft. http://www.swtor.com/community/showthread.php?t=47695 Enjoy!