The first things that came to mind while reading your post was that either your shoes are too tight or you're not getting enough support/cushion from your shoes.

Your shoes could be laced too tight, or not fitted properly so they constrict your feet and in turn, cut off circulation.  Try to tie your shoes so that your toes can move upward when you point them up and make sure that the top of the shoes (area closest to your ankle and the tongue of the shoe) has a bit of wiggle room.

Your shoes, being that they are old, may not be giving you all of the support or cushion your feet need.  The only solution to this is to get new shoes ASAP.  Shoes are the most important piece of equipment every runner uses, so you need to make sure that you are getting exactly what you need out of your shoes, skimping here could cause injury.  You should go to a good running store (NOT a general sporting goods store) and be properly fitted.  The staff at a reputable running store will be able to put you into shoes that give you exactly what your feet require.  You don't have to spend a fortune, but you don't want to buy a shoe just because it is the cheapest either. 

Good luck and I hope that you feel better soon!