Can I take ativan? If so, how long before the flight?

Hello, I am claustrophobic and I am flying tomorrow. I thought that everything was under control and that I would be able to take the plane without panic, but I just had a panic attack. My heart was beating fast and I could hardly breathe. My fear is that I won't be able to control my anxiety attack, that I'll pass out and that we'll have to land because of me. I have no health problems or allergies. I don't smoke or drink. I don't take medication every day.