Handful of issues out of no where car won't run! Electrical maybe???

So I don't know where else to turn to, about 4 weeks ago I lost second gear randomly and decided it to not drive the car until my new trans got here, however 2 weeks ago when I started the car again I noticed the car had the battery light and check engine on with 4 codes (camshaft position sensor, 2 02 sensor heater circuit codes, and evap vent circuit low). Drove the car for a little noticed a buzzing sound coming from my speakers(Rockford speakers connected to a 5 channel amp that goes straight to the battery). And today when I went to start the car the battery was drained! Lights still dimly came on but no crank or start , battery light and cel light on, jumped the car and turned it on but the battery doesn't charge itself and the lights dim after disconnecting power and the whole car (gauges lights stereo) begin to turn on and off as if your turning the key on and off (they are also very dim) and during my last attempt the Airbag light I belive (the red dude with his hand up) came on and idk what to do. I'm a noob with the Rsx as I just got the car about 5 months ago and never really had issues with it, tried researching the best I could but nothing seems to relate! Any help or sense of direction on what could be wrong would be greatly appreciated!!

Handful of issues out of no where car won't run! Electrical maybe???