HELP! car alarm is acting insane!

This has NEVER happened before! Just earlier, when I got into my car, the alarm goes on for no apparent reasons. The car was locked, and I unlocked it with my key, nothing unusual. Suddenly, the alarm goes on in the parking lot, and I could not shut it off with my key in the ignition. I drove home with it coming on and off every 30-60 seconds with lights flashing.

What is wrong? I could not turn it off except when I got home and quickly turned off engine before the next alarm burst. HELP! It was embarrassing driving home with my alarm going on and off!

This may be a stupid question, but could you do any damage to the car when driving with alarm on and lights blinking? Car concerned is a 1990 190E. Thanks.

Nice update to the page, btw!