Shin splints usually are noticed on the shins ( ! ). And they don't go away in seconds, but you may be able to get through them in a mile or two. Sounds like you had some cramping. Keep an eye on it so you don't end up pulling a muscle.
Congrats on the weight loss. Shin splints come in 4 varieties Posterior Tibial pain, Tibial Periostitis, Comparment Syndrome and Stress fractures. None of these go away in a mater of seconds,minutes or even days. Like someone mentioned it was probable a spasm from the exertion from the previous day.