Foot/toe injury

Hi,
Can anyone help me diagnose the pain/feeling I have in my foot/toes?
I returned from holiday in early November where I did a bit more running that usual.  I flew back and did a parkrun the next day (PB btw!).
It was after that I noticed a pain in my right foot.  I say it was a pain but it was more of a feeling, a kind of numb sensation across the end of the foot where he toes are.  The first time I tried swimming after this I felt a strong pain on my big toe while kicking doing front crawl, but nothing else which felt strange.  I've rested it over the last few months as much I can and the big toe pain has gone.  However I have tried a few runs and the numb sensation returns if I push it too much.  I'm guessing it might be a trapped nerve or something...any ideas?

-Marc