Major twist, Minor Sprain (in ankle)

I was on a trail run with a group about a week ago and 4 miles into the trail I twisted my right ankle pretty good.  It hurt pretty bad at first, but I was able to walk a mile home with no problems.  I have no swelling, can walk completely fine on it and can even jump up and down.  I have alternated compression and ice and elevated it, also resting it when I am able to (I have a toddler and am a busy mom).  Yesterday after taking 6 days off from running and my ankle having no pain what so ever, I went for a 4 mile run to test it out.  It didn't hurt at all while I was running with the exception of occasional soreness, but nothing major.  When I came home I stretched my achilles tendon and iced my ankle as well as compression for good measure and still had no pain.  When I woke up this morning I still had no pain but as the day progressed the dull soreness came back and when I twist my foot suddenly when I get up I have a quick sharp pain shoot across my foot, but then dissipates.  

I have very faint bruising under my veins that cross over what appears to be the Extensor Digitorum Brevis muscle and it is slightly puffy, not much, but a little bit in the bruised area.

Would this be considered a sprain, and if so how severe?  Everything I have read doesn't fit my profile in terms of the type of pain I have as well as other symptoms, or lack there of.  

I am training for a half marathon that is 4 weeks away and want to make sure my foot is ready to go, but if it isn't anything major I don't want to hault my training either.  Any help would be great, thanks.

Monica