I am worried about the asteroid that will fly by next Saturday , plus why is it that nasa did not see the asteroid that flew. By yesterday?

How do you know NASA did not see it??
Have you looked at the Chart of Near Earth Asteroids??
www.spaceweather.com

NASA saw both, but when the asreoids MISS YOU by a million mile or more, they just are not important.

For that matter, anything farther than 100,000 miles is a miss, and flu nvm ts for nothing.

For comparison, the moon is 250,000 miles aware

The closes that Phaeton will get to the Earth nest Saturday will be more than 6.4 million miles, more than 27 times farther away than the Moon.