Could this be the flu?

It's a little complicated but here goes. Friday a week before last (the 18th), I came down with a sinus infection that lasted until about Monday or Tuesday (21,22). Around that time, I also got a bladder infection and Wednesday started a prescription of Macrobid for that. By this time, my sinus infection was mostly gone. I was feeling fine the rest of the week, until Sunday (27th), when I woke up with excruciating pain in both arms, from the shoulders down through my palms, chest pain and a bad headache with light sensitivity. I frequently get migraines, so I wasn't too worried about the headache, although it felt more like a tension headache and Excedrin didn't seem to help at all, so I thought that perhaps I was having a reaction to the Macrobid, and I stopped taking it that day. Monday (yesterday) I had a temperature of 102 and a slight sore throat, so I went to my doctor's office and saw a PA, who assured me that it was only the flu. Today, I still have the headache, which has only worsened, photophobia, my hands and arms feel bruised, I have a slight fever (between 99 and 100), chest pain, difficulty breathing, severe upper back pain and a mild sore throat. I do NOT feel weak and or shaky, as I've always felt before with the flu, and while I feel slightly nauseated, I haven't been vomiting. I also occasionally feel like bursting into tears, but I don't know if that's related. Anyway, my question is, do I have the flu? Or could it be something else and should I go back to my doctor?

Thanks