My in-laws started feeling badly last week and went to get tested over the weekend but had to wait for results. On Monday night, my 8-year-old daughter spiked a 104-degree fever. Needless to say, we were concerned. Thankfully Tylenol brought her temperature down to a manageable level and we were able to get her in to see the pediatrician first thing the next morning, where she tested positive for COVID. My wife and I both also got rapid tests done that day at different locations and we both tested negative. At that point I had felt like I was coming down with a cold/flu for a couple of days - didn't feel terrible, but I had some chest congestion and just felt "off". Given that a member of my household had tested positive, my doctor's office decided to also do a PCR test to confirm my diagnosis and said it would take up to a week to get the result.

Since then my daughter seems to have bounced back to normal. She only had the fever for about 12 hours, and her only other symptom was nausea and vomiting in the first 24-36 hours. Today she seems virtually back to normal, although her appetite is still a bit muted. Yesterday both of my in-laws got positive test results back, so they are likely where we picked up it over the holidays. Their symptoms began several days before my daughter's, so it seems most likely that they were the "patient zero" in our family circle. We did not have a large family gathering with them - it was just my wife, daughter, me, and my wife's brother at their house on the Sunday after Christmas. I came back home the same day, but my wife and daughter stayed for 2.5 days. Somehow my wife does not seem to have contracted the virus from her parents or our daughter. I, on the other hand, feel like I probably have a mild case of COVID (as of now), despite testing negative. Today my PCR test also came back negative, but I am also feeling a slight scratchy throat and have had some coughing episodes/chest congestion tonight.

I really can't wrap my head around our results, other than two hypotheses:
1) The testing is extremely unreliable
2) Some people don't shed virus even if they are in fact infected

I'm not sure how else to explain situations like this.