So I bought my car about a month ago, and everything works good, but about a week after I bought the car the battery went dead. However I thought what caused this were the lights on the rearview mirror which wouldnt turn off, so I put the switch halfway in order for them to turn off. After this I disconnected the connector for these lights, but today I went to turn on my car and it tried to turn over but very weak and finally just started clicking. So my question is do I have a short somewhere or what could be causing this? by the way my battery is an optima red top

Thanks in advance,
Alex