1999 Buick Lesabre Broke something hitting deep hole

Hi, I ran over a sewer cover in the road and it was set very deep in the cement. I hit the hole with my right front tire. I was going about 30 mph. As soon as I hit the hole, there was a huge thump/bang type noise that now happens on and off while driving it. It clunks so loud, I can feel it in my feet. It is under the engine. It will thump or clunk heavily with a slight bounce of the car on the road, with a small bump and sometimes while turning or taking off from a stop. The car is driving fine except for this awful noise that is very scary.

I drove it 40 miles today and all was fine but I am uneasy that something is going to fall apart any minute. I was wondering if you can guess what it is and how serious it is that I should take it in right away, which is nearly impossible for me to do at this time. Will it hurt more to keep driving it or is it just a nuisance noise. How urgent do you think the problem is? Thanks.