Bizarre foot complaint

was just wondering if anyone had any suggestions...its my left big toe and its not completely numb, as i can feel my own touch, but it feels a bit sort of distant as if all the feeling isnt quite there. it was numb after yesterdays run (12 miles training pace) and again after todays (10k but only about mara pace)...i dont know if it recovered in between as i didnt think to check. i have a vague feeling that i had this once before, with both toes, when spring marathon training but i cant remember what run/race it was after.

quick summary: i have wide feet at the front and narrow heels, i also have quite bony feet, so i cant lace my trainers up tight enough to stop my heels from slipping out a little when i run as it hurts the top of my foot. im a neutral runner and recently changed to mizuno wave creation 9 shoes (previously asics gel kayano). i changed brands after my marathon as i got a black toenail on my pinky toe so figured the gel kayanos were a bit narrow for me.

any thoughts?

Not sure about the numbness - might be either the shoes a bit tight or perhaps "Clawing" the toe to grip.

As for the fit - if you haven't already then try loop lacing, and if that doesn't work then a trick I use is to cut off bits of an old insole about 3cms by 1cm and stick them on the inside of the shoe just in front of the heel using double sided sticky tape to get a better grip.  Worked a treat for me and without any extra cost if it hadn't done the job