We need the exact year of your car, also the battery may be shorted internally or have a dead cell so you should charge it up fully, to save time, then take it to your local auto parts store for a free test. If it is good then we can help you find the parasitic drain in your car. This test will involve an amp draw test which will use a multimeter, do you have a multimeter that can test amps? If you have one, do you know how to use it properly to test amps? Here is some help.
https://www.youtube.com/watch?v=KF1gijj03_0