So im posting this in hopes someone can help me troubleshoot what's going on with my ac.

Ac was blowing hot for a while so I evacuated the system, and pulled a vacuum to recharge. the ac worked perfectly for about a week then the problems started to hit me.
Ac blew hot once again but ac still comes back once the car has been parked for a good 30 minutes.
now Ac is making a weird humming sound whenever the car's ac turns on initially almost like it's trying to lube something then it gets lubed and the sound goes away. (I'm hoping that it's not oil on my ac compressor or something)

I suppose one of my main current questions is whether should I have added more oil into the system before recharging? I was under the assumption that no oil would be needed as pulling a vacuum wouldn't remove oil from system.

Attached below is the sound that the car makes once I turn ac on then try to turn the car off to get a better recording of the sound.

 

is the ac line in the engine bay cold & NOT frozen?