Won't let me record in existing track anymore

I have been using audacity for years and have never had this problem. This was working just fine for me five days ago now it has stopped. When I record, I press the space bar to stop the track, I delete my mistake and press shift+R to continue recording on the existing track, that option, has completely disappeared for me. It ALWAYS create a new track no matter what I do. I can not record like this, I have searched the Manuel, downloaded an older version o audacity checked my settings and have no idea what to do. I have to be able to stop recording, edit and then continue on the same track, please help! It always creates a new track, the only way it doesn’t if is I press the P key to pause recording, I have never had to do that before, space then shift R use to work and per the help
Guide it is suppose to continue that way, even the older verisons are doing the same. I have a deadline and I need audacity to complete this work.

See if it’s still broken if you restart the computer.

If so, see if Shift-R is still listed in the keyboard shortcuts.

Audacity > Edit > Preferences > Keyboard: Key. Scroll down.

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