1999 Corolla Bad Vibrations

I have a '99 Corolla with about 185,000 miles. While going over bumps in the road, I hear a rattling sound. Also, if I engage the clutch too quickly or sometimes shifting into reverse, I hear a clunking sound, and worst of all, at highway speeds, my car sometimes vibrates very excessively to the point I get an overkill hand/rear massage. It is especially bad if I take the on-ramp too quickly (>30 mph). Could you let me know what could be the problem and how severe the problem could be?

The rattling has been going on from the time I purchased the car, and I've had vibrations from flat spots on the tires, but I want to make sure there isn't something serious that could cause an accident at 70 mph. Thank you for your help!

Also, the rattling/clunking sound comes specifically from the front-left of the vehicle.