I Was Diagnosed With Pneumonia In My Left Lung 2

I was diagnosed with pneumonia in my left lung 2 weeks ago. I have been fever free for 9 days and released to return to work yesterday. Yesterday after lunch, I felt awful, took my temp when I got home at 5pm to learn I had 100.7. I had chills and fever most of the night. I felt better when I woke, so I went back to work. It's 3pm now and I'm beginning to feel worse and my temp is 99 currently. Is this normal after pneumonia? Should I return to my doctor?