Do my partner and I have the same sickness? Or something else?

So over the weekend, I was feeling under the weather and had to take it easy on the socializing. Sore throat and slightly runny nose, but nothing major. I was mostly better by Sunday and felt nearly 100% by this afternoon.

My boyfriend started getting similar symptoms a day or two ago, but now his has turned into more flu-like symptoms. Last night, against my advice, he took a nap from like 4–7pm and then ended up staying up reading until 3 am. Today he got worse, and he went to the doctor who prescribed him some meds, and hopefully, he’ll start to recover in the next couple of days.

Is it possible that we have two different illnesses or did he just catch what I had but worse?