Hey, twenties girl. Yes, you are an addict. It's called being a binge user. A person can go for weeks or even months w/o their drug of choice, but when they start, they can't stop. And usually bad, humiliating things start to happen. There are many many bingers in my meetings. Sounds like you have already admitted it, so that's the first step. Good for you. I know how scary it is to get help. But, we either get better or we get worse. Just go to an NA (or AA) meeting. You don't have to talk. Just sit and listen.
Like Sarah said, stick around and keep talking to us.
You have already answered your question about being addicted. You have crossed that line and now it will only get worse until you completely walk away. The first step is admitting you are powerless over these drugs and second, you need to change your playmates and playground. The drug game is a deadly game and none of us are exempt. Paranoia has already set in for you along with the lack of euphoria. We all understand what you are going thru as we have been there. We are also here to let you know there is hope and recovery. I hope you stick around and talk to us.
(And yes this is one of those occasions. Party was Friday night and have since picked up 3 times and dreading having to finally go to bed)