I keep trying to upload my code into the Uno and the port is gone plz help
Is there anything in Tools -> Port? Windows will give it a different port number if you plug it into a different port.
What platform are you on?
What were you doing immediately before it stopped working?
Have you tried plugging it into another port?
Does it show up in device manager? Do any unknown devices show up in device manager?
If you're using Windows, check the device manager; anything with exclamation marks / yellow triangles? Did you install any additional software since the last time that it worked? Specifically software that makes use of USB (e.g. for a cell phone).
No idea for other operating systems but dmsg will probably your friend in Linux.
If you are using USB3 port and have USB2 ports on your PC, give them a try.
depending on the Windows version there are a lot of problems reported here when using USB3.
Another issue sometimes comes from using a USB hub.