2001 Pontiac Bonneville Oil pressure guage

My car isn't noticably leaking oil. My oil pressure guage for the last week has been fluctuating. From 20-80. 2-3 days ago started dropping down to 0 and red area n setting off my dummy dinger. The car was not making any noticeable noises until It started dropping to zero. Then it loses power. And I can hear a slight miss while if I'm at a stop or idle and pressure drops to zero. What are some things I can check to remedy this issue? I'd like best and worst case scenario and all In between if possible. Thanks