viral infection heavy legs?

Last week I felt really weak & achy all over. I had a low grade fever, headache, no appetite, weak & heavy feeling all over-esp in legs. I went to dr did a flu test came back negative. He said it was a viral infection and sometimes viruses can attack nerves & muscles. I even had blood tests done everything was normal. I am feeling better but my legs still have that heavy feeling still feel weak, improving but just wondering if this is normal??