About a month ago, I bought an 05 Altima. About a week and a half ago, I got in and turned the key, but nothing happened. All the lights went out, and it seemed like it was dead. I popped the hood and checked the positive battery terminal to make sure it wasn't loose, but as soon as I moved it everything went back to normal. Since then I've been having this problem every other day, sometimes multiple times a day. All I have to do is wiggle the terminal and everything is fine, but I'm tired of having to reset my radio settings all the time. Plus it's embarrassing to have to do this in public. What should I do to fix this issue? I'm worried that it's going to cause issues with the rest of my electrical system. Any suggestions would be helpful.