I Was In A Cast For 3 Weeks NWB For

I was in a cast for 3 weeks NWB for a 5th metatarsal fracture or the proximal shaft. After 3 weeks I was x-rayed and told was healing but could still fracture line. My orthopedic surgeon gave me a thick soled ortho shoe to wear and told me to gradually bear weight every week for 6 weeks till I see him. He said he would rather treat this without surgery. Im currently on my third week of weight bearing and about a week ago I started getting extreme pain in my calf and ankle. I assumed it was tightness or pain from not using my leg for over a month but the pain has been persistent for a few days now and stretching doesn't seem to help. I contacted a nurse advice line to get advice because I have heard it is possible to get blood clots while recovering from a fracture but she said my symptoms don't sound like a blood clot because I have no swelling most likely its from not being mobile for so long but to watch for any changes in my leg.. I am still kind of of worried because the pain doesn't seem to go away am I just being paranoid? or should I go the ER?