Alarm problems

I stopped for gas today and when I got back in my car to start it the alarm went off. The car wouldn't start and the door locks were going crazy going up and down real fast. I could hear loud clicking going on under my dash at the same time. I tried the remote thinking I might have hit the panic button but nothing worked to shut it off. I popped the hood the try and pull the negative terminal but it was on tight. The alarm kept resetting and going off again and again. I found a guy with some pliers and got the terminal off. Every time I put it back on the alarm started the cycle all over. I finally found the bypass button on the kick panel and got it to stop. I cut the wires to the siren so I could trouble shoot it as every time I tried to start the car it would start going off again. I found that holding the bypass and turning the key let me get the car started and back on the road. I got home and cleaned up my terminals as they were dirty. Everything works now but when I go to start the car I have to hold the bypass button for it to start.
Does anyone have a clue to what happened or how to get the alarm system back to where it was before all this.