Bodyguard/Combat Medic really takes a while to come together -- you really start coming in line right around level 30 and are pretty close to fully powered at you enter the mid 40s. I guess that qualifies the AC as a late bloomer? Once you get your 31-point skill and start getting some of your heat maintenance options, you should be able to survive longer on raw healing output. Lowbie is rough in my experience as any healer until halfway through the leveling curve, just because DPS tend to get their key abilities and procs sooner and there tends to be ALOT of deathmatching in lowbie (two ingredients which make healing a pain in the neck).
Let me put it this way, the class has the highest learning curve of the healers but eventually becomes the most durable of the healers. It just takes time, experience, and gear.
Thanks for the input. What build do you use?