A pain in the...... heel

So for the past couple weeks I've been feeling this twinge in my heels, especially my left heel that has slowly gotten worse. I'm pretty sure it's plantar fasciitis, which I've never had before. I've got the typical symptoms- it's worse when I wake up in the morning (which is of course when I run) or after a prolonged period of sitting (which is what I do at work all day). It's not unbearable, so I'm doing what I always do, running anyway. I'm always reluctant to stop running, especially since I'm actually seeing some progress with the weight-loss, I'm down to an even 140 pounds. But it's making my runs not much fun, and I'm starting to worry that I may be doing permanent damage.