As someone else pointed out, it doesn't matter what you call it. It's a bone stress injury. I had a similar issue over the past few weeks and couldn't tell at first if was a stress fracture or just a stress reaction, a precursor to a stress fracture. Like you, I also didn't have spot pain. My initial symptoms were slight discomfort when walking several hours after my last run and some pain along the right medial shin over several inches below the knee when I pressed on it.
FWIW, shin splints are more common in the first few weeks of running after a layoff, but for someone who's been running regularly, as in my case, they're less likely.
Now, I've had many stress fractures over the years (will be 40 next month), and had never caught the injury early enough to avoid it from progressing from a stress reaction to a stress fracture. Unfortunately stress fractures come on suddenly with little warning signs. Often you can figure out if it's a stress fracture by doing the hop test. Another decent gauge is if the pain is at the beginning of a run but subsides as you warm up, you're dealing with shin splints. Pain from a stress fracture will not go away as the run continues. The hop test was inconclusive for me. I could tolerate it, but didn't feel great. I wasn't going to run again to test it, because in theory I was only one run away from a stress fracture, if it wasn't already.
What did I do? I stopped running. Complete rest, no cross training for about 5 days. Since I didn't have any pain walking (only when pressing on the shin) I began walking 30 minutes each day for another 5 days or so. As I had no pain whatsoever during or after those walks, the odds in my estimation that I caught it early enough to prevent a stress fracture were increasing with every walk. After 11 days of no running, I started my return to running program. First day was (4.5 min walking/30 sec running) x 6 = 30 minutes for about 2 miles. So mostly walking, with a little bit of running. As I didn't have pain during or after, I continued with my return to running plan. Each day, more of the 30 minutes was made up of running and less walking. Each day I monitored any signs of discomfort (before, during or after). It's now been 6 days and today I did (30 sec walking/4.5 min running) x 6. So mostly running, with a few short walk breaks. All good so far. I can now say with confidence that I caught it before it became a stress fracture. Moral of the story, listen to your body. Every step along the way is predicated on an assessment of how your body is responding to your activity. If I had had pain at any time, I would have stopped again and took more time off.