I am sick. Whole household tested positive for covid on rapid test but I tested negative on rapid test?

You need to assume that you have the coronavirus and get the other test. Absolutely quarantine.  If you are sick you most certainly have it.  

A friend of mine's mother tested negative for covid 4 times before testing positive.

You all need to start taking 5000UI of vitamin D3.

if it's still within 3 days of testing positive, see if you can get the Regeneron or Eli Lily covid antigen treatment.

In response to Gypsy:

Where do you live that everyone is allowed to be vaccinated?

In my area, we are currently at the under 50 with pre-existing conditions people. 

The only people I know that are under 50 who have been vaccinated are a 23yo with a kidney transplant and essential workers. 

anything is possible

A smart person would have opened the windows and spent as much time outside as possible

Yes, if you're having the symptoms, you.have COVID. Didn't get yourself vaccinated did you? Did you think you were immortal? 

If you are just as sick as they are, I think there is a good chance you will test positive.