Pain on the top of my foot...stress fracture??

I've been running cross country and track for 6 years and my body seems to be freakily resilient since I've never gotten injured except for shin splints once. Recently, however, I've had this pain on the top of my foot, just where the 3rd metatarsal is. I'm not sure what it is exactly...stress fracture, tendon strain, or something else. My foot doesn't hurt when there's no pressure on it, but when I'm walking or running it hurts. Usually its a sharp pain (it hurts especially if I've been sitting for a long time and suddenly start walking, like when I wake up in the morning); but after I've been walking for a while it dies down a bit. It started not that bad, only an ache, then it went away for a couple days, then it came back again, and it's been on and off for the whole time. Just a week ago it came back again but this time it was a worse and sharper pain than before and it hurts to even walk, not just when I'm running like before. The pain is centered in that one area (middle of the top of my foot, an inch away from my toes), and it hurts when I press on that spot but not when I press around it. It's not from overtraining because track just ended and we've been winding down, not increasing mileage or intensity.

I don't think the pain is bad enough for it to be a stress fracture yet, but I fear it could be the beginnings of one and that if I don't take enough time off to let it heal it will only get worse and I'll end up not running for even longer. I've already taken almost 2 weeks off and the pain is still there.

If you have any experience with this, do you know what it could be? Is it a stress fracture? And if I should take more time off (I probably should) how much? And are there any foot exercises or things to do (besides icing) to make it get better faster?

I hope you can help and thank you so much.