My car will not go into gear while it is running?

I have a 1998 Honda Prelude. This morning, I started it up and it was fine. I went to the gas station to get gas, turned the car off, then when I turned the car back on, it would not go into any gear. I found I have to put it in gear first, then start it, but then the first time it stalled, then it bucked real hard forward. I finally got it running and while I was driving it was fine, but whenever I can to a red light, I had to keep the clutch engaged and keep reving the motor. Can anyone help me?