Hi welcome to healthcare magic forum. It appears that there might be a hair line fracture
of metatarsal, or tarsals. you would have a weight bearing , or brisk walk afterthe visit to the doctor. and it ha unimpacted causing pain.
But during sprain
also after physical strain the pain may be started.
As you are stating that you can't afford to see the doctor again, i advise you to continue the medicines prescribed by the doctor, and have one more dose of analgesic
for pain relief. minimise the weight bearing and long walks, for few days, because the treatment consists of immobilizaton of the part for few days.
I also advise you to follow some diet recommendations as avoid taking potato, other tubers, tomato, cauliflower, coconut, egg, chicken and sea foods, as these may increse the pain when it is there. After pain is controlled you can take all these foods again.
Wishing for a quick recovery and thanks for calling.