Was starting to feel better from pneumonia, now really sick again?

I've had pneumonia for about 2 weeks now, and I went for a follow up yesterday with my doctor and was feeling a lot better. My fever had been gone for a few days, but within hours after returning home my fever spiked and I was extremely sick again. It wasn't so much the chest breathing, but I got congested, had chills and sweats, muscle ache and a fever of around 102 since. Is this something that happens a lot when you have pneumonia?