TII-aholic

Ok so about a week ago i started having some issuees with my starter. It was kinda of an intermitant thing. sometimes it worked and sometimes i got nothing. So i thought maybe its the starter brushes. so yesterday i replaced the starter brushes and I put the starter back in and I turn the key.......nothing . so im like whatever ill take care of it later. I bump start the car and did that like twice last night. Everything seemed fine. I wake up this morning and go out to the car and when i turn the car to on I got nothing. my battery is dead. So somehow the battery drained last night while i was asleep. ok so heres my question. If it wasnt the starter brushes causing the starter to be intermitant what could it be? also why the heck is my battery draining now all of a sudden? the battery is practicly brand new I got it about a month ago.