Your experience is not even remotely similar to the one I had leveling a JK to 50, did I die sometimes, sure I did. However that was generally when I either made mistakes, was not really paying attention, or didn't react fast enough to some new abilitys that a type of enemy I had not encountered before was using.
On saying that there was no single player content that I did not complete on my own in short order, and I steam rollered most of it.
The class has several extremely powerful defensive cds with a very good uptime, rebuke being the pick of the litter. Proper use of force kick, stasis and awe also lower the incoming damage greatly, as does the short stun from force sweep (when engaging packs of normals) for that matter.
Learn to use these abilitys correctly while still hitting like a freight train, which is what we do, and really you should not struggle.