Need help, battery draining issue

Last week all doors opened warning light used come up on and off for couple of days. Fueled the car at a different gas station for the first time an ended up parking the car on the curb with right back wheel on the curb. After realizing this, tried to park correctly but the "P" was not done correctly error came up and couldn't even start the car. Being late friday evening, couldn't get the tow and ended up leaving the car as is and looks like the battery was drained. Saturday morning, tow came and with jump start, was able to start the car and drove around 20+ minutes and parked the car. Started the car again to make sure its starting without any issues. Didn't had to drive on sunday but monday morning, battery is drained completely again.

Prior to this there are no noticeable changes in the speed/mileage/dash and everything was normal. The mileage on the car is around 151K. What should I do now, give a jump start and hope it will work or what kind of testing should I get it done. I am in bay area and am a previous Luscious Garage customer and should I get the car checked out? Have a scanguage as well and is there something I can check?

 

On and off I check the voltage and around last week it was still 14.1 when ignition was on. My mpg was still around 46/48. Battery may be over 5 years old though and will look to replace that.

 

Thanks for the reply both of you. I ended up replacing the 12v battery and cost me around $265 including parts and labor. The battery that was replaced was from 2005! 10 years of service. wow.